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Background: The senescence marker p16INK4a, which constitutes part of the genome 9p21.3 cardiovascular disease (CVD) risk allele, is believed to play a role in foam cells formation. This study aims to unravel the role of p16INK4a in mediating macrophage foam cells formation, cellular senescence, and autophagy lysosomal functions., Methods: The mammalian expression plasmid pCMV-p16INK4a was used to induce p16INK4a overexpression in THP-1 macrophages. Next, wild-type and p16INK4a-overexpressed macrophages were incubated with oxidized LDL to induce foam cells formation. Lipids accumulation was evaluated using Oil-red-O staining and cholesterol efflux assay, as well as expression of scavenger receptors CD36 and LOX-1. Cellular senescence in macrophage foam cells were determined through analysis of senescence-associated β-galactosidase activity and other SASP factors expression. Meanwhile, autophagy induction was assessed through detection of autophagosome formation and LC3B/p62 markers expression., Results: The findings showed that p16INK4a enhanced foam cells formation with increased scavenger receptors CD36 and LOX-1 expression and reduced cholesterol efflux in THP-1 macrophages. Besides, β-galactosidase activity was enhanced, and SASP factors such as IL-1α, TNF-α, and MMP9 were up-regulated. In addition, p16INK4a is also shown to induce autophagy, as well as increasing autophagy markers LC3B and p62 expression., Conclusions: This study provides insights on p16INK4a in mediating macrophages foam cells formation, cellular senescence, and foam cells formation., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: The association between p16 INK4a and p21, a marker of cellular senescence, and the Immunoscore, an immunological prognostic indicator, in rectal cancer patients undergoing curative surgery were investigated., Methods: A total of 82 patients who underwent curative surgery for rectal cancer were evaluated. The resected specimens were analyzed for p16 INK4a , p21, CD3 and CD8 expression by immunohistochemistry. Immunoscore was calculated on the basis of CD3 and CD8 expressions. The clinicopathological characteristics and long-term outcomes were evaluated., Results: Among the 82 patients, 24 (29.3%) were p16 INK4a -positive and 11 (13.4%) were p21-positive. The patients were classified into the following five Immunoscore groups (IS0-5). IS0, IS1 and IS2 were classified as the low Immunoscore group (45 patients, 54.9%) and IS3 and IS4 as the high Immunoscore group (37 patients, 45.1%). There was no significant difference in age, sex, body mass index, American Society of Anesthesiologists physical status, depth of invasion of the tumor, lymph node metastasis and histological classification of the tumor with p16 INK4a or p21 expression or Immunoscore. p16 INK4a -positive expression and low Immunoscore each showed a tendency to indicate poor prognosis of disease-free survival (DFS). Patients with the combination of p16 INK4a and p21 positivity and with p16 INK4a positivity and low Immunoscore showed significantly poor prognosis of DFS. Patients with p21 positive positivity and low Immunoscore tended to have worse DFS., Conclusions: p16 INK4a , p21 and Immunoscore may be prognostic indicators of rectal cancer. The combination of them may provide more accurate prognostic prediction than either factor alone., (© 2024. The Author(s) under exclusive licence to Japan Society of Clinical Oncology.)

Cathepsin L (CTSL) has been implicated in aging and age-related diseases, such as cardiovascular diseases, specifically atherosclerosis. However, the underlying mechanism(s) is not well documented. Recently, we demonstrated a role of CUT-like homeobox 1 (CUX1) in regulating the p16 INK4a -dependent cellular senescence in human endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) via its binding to an atherosclerosis-associated functional SNP (fSNP) rs1537371 on the CDKN2A/B locus. In this study, to determine if CTSL, which was reported to proteolytically activate CUX1, regulates cellular senescence via CUX1, we measured the expression of CTSL, together with CUX1 and p16 INK4a , in human ECs and VSMCs undergoing senescence. We discovered that CUX1 is not a substrate that is cleaved by CTSL. Instead, CTSL is an upstream regulator that activates CUX1 transcription indirectly in a process that requires the proteolytic activity of CTSL. Our findings suggest that there is a transcription factor in between CTSL and CUX1, and cleavage of this factor by CTSL can activate CUX1 transcription, inducing endothelial senescence. Thus, our findings provide new insights into the signal transduction pathway that leads to atherosclerosis-associated cellular senescence.

Background and Objectives : Human papillomavirus (HPV) was previously investigated in lung cancer with wide inter-geographic discrepancies. p16 INK4a has been used as a surrogate for detecting high-risk HPV (HR-HPV) in some cancer types. This study assessed the evidence of HPV in non-small-cell lung cancer (NSCLC) among Jordanian patients, investigated the expression of p16 INK4a , and evaluated its prognostic value and association with HPV status. Materials and Methods : The archived samples of 100 patients were used. HPV DNA detection was performed by real-time polymerase chain reaction (RT-PCR). p16 INK4a expression was assessed by immunohistochemistry (IHC). The Eighth American Joint Committee on Cancer protocol (AJCC) of head and neck cancer criteria were applied to evaluate p16 INK4a positivity considering a moderate/strong nuclear/cytoplasmic expression intensity with a distribution in ≥75% of cells as positive. Results : HPV DNA was detected in 5% of NSCLC cases. Three positive cases showed HR-HPV subtypes (16, 18, 52), and two cases showed the probable HR-HPV 26 subtype. p16 INK4a expression was positive in 20 (20%) NSCLC cases. None of the HPV-positive tumors were positive for p16 INK4a expression. A statistically significant association was identified between p16 INK4a expression and the pathological stage ( p = 0.029) but not with other variables. No survival impact of p16 INK4a expression was detected in NSCLC cases as a group; however, it showed a statistically significant association with overall survival (OS) in squamous cell carcinoma (SqCC) cases ( p = 0.033). Conclusions : This is the first study to assess HPV and p16 INK4a expression in a Jordanian population. HPV positivity is rare in NSCLC among a Jordanian subpopulation. P16 INK4a reliability as a surrogate marker for HPV infection in lung cancer must be revisited.

Purpose: The ocular surface microenvironment changes with aging. However, it remains unclear if cellular senescence influences the ocular surface. We investigated the presence of p16 INK4a -expressing senescent cells in healthy human conjunctiva., Study Design: Clinical and experimental., Methods: Healthy conjunctival tissue samples were obtained from middle-aged and elderly subjects. RT-qPCR was performed to assess the expression of senescence markers CDKN2A (p16 INK4a ) and CDKN1A (p21 CIP1/WAF1 ) and immunostaining was performed to examine the expression of the senescence marker p16 INK4a , stem cell markers Ki67 and p63, tight-junction marker ZO-1., Results: Our study involved 19 conjunctival tissue samples (10 elderly and 9 middle-aged), mean age [elderly: 75.8 ± 3.7 years (72-81), middle-aged: 52.7 ± 7 years (38-59)], sex (elderly: 3 men, 7 women; middle-aged: 3 men, 6 women). The expression of p16 INK4a was significantly increased at the RNA level in the elderly compared to middle-aged (p < 0.05). Positivity rate of p16 INK4a was significantly elevated in the elderly (15.0 ± 7.8%) compared to middle-aged (0.2 ± 0.6%) (p < 0.05). Positivity rate of Ki67and p63 was significantly reduced in the elderly (1.7 ± 1.7% and 16.5 ± 9.5%) compared to middle-aged (3.9 ± 1.8% and 24.7 ± 5.7%) (p < 0.05). ZO-1 expression was reduced in tissue samples showing p16 INK4a -positivity but retained in tissue samples in which p16 INK4a was undetectable., Conclusions: Senescent cells accumulate with age in the conjunctival epithelium, accompanied by a decrease in Ki67, p63 and ZO-1 expressing cells., (© 2024. Japanese Ophthalmological Society.)

Glaucoma is a leading cause of irreversible blindness, with advanced age being the single most significant risk factor. However, the mechanisms underlying the relationship between aging and glaucoma remain unclear. Genome-wide association studies (GWAS) have successfully identified genetic variants strongly associated with increased glaucoma risk. Understanding how these variants function in pathogenesis is crucial for translating genetic associations into molecular mechanisms and, ultimately, clinical applications. The chromosome 9p21.3 locus is among the most replicated glaucoma risk loci discovered by GWAS. Nonetheless, the absence of protein-coding genes in the locus makes interpreting the disease association challenging, leaving the causal variant and molecular mechanism elusive. In this study, we report the identification of a functional glaucoma risk variant, rs6475604. By employing computational and experimental methods, we demonstrated that rs6475604 resides in a repressive regulatory element. Risk allele of rs6475604 disrupts the binding of YY1, a transcription factor known to repress the expression of a neighboring gene in 9p21.3, p16INK4A, which plays a crucial role in cellular senescence and aging. These findings suggest that the glaucoma disease variant contributes to accelerated senescence, providing a molecular link between glaucoma risk and an essential cellular mechanism for human aging., (© 2023 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Retinal astrocytes are vital for neuronal homeostasis in the retina. Together with Müller glia, they provide retinal cells with neurotrophic factors, antioxidative support, and defense mechanisms such as the formation of the blood-retinal barrier. Substantial heterogeneity of astrocyte morphology and function represents a challenge for identification of distinct subtypes which may be potential targets for therapeutic purposes. Hence, identification of novel markers of astrocyte subpopulations is highly relevant to better understand the molecular mechanisms involved in retinal development, homeostasis, and pathology. In this study, we observed that the cell cycle regulator, p16 INK4a , is expressed in immature astrocytes in the mouse retina. Immunohistochemical analysis showed p16 INK4a expression in the optic nerve of wild-type mice from 3 days to 3 months of age and in the nerve fiber layer of the adult mouse retina. Colocalization of p16 INK4a expression and glial fibrillary acidic protein (immature/mature astrocyte marker) tends to decrease with age. However, colocalization of p16 INK4a expression and vimentin (immature astrocyte marker) remains high in the optic nerve from the early postnatal period to adulthood. The observations from this study provide a valuable tool for further investigations of ocular astrocytes in the developing retina as well as in degenerative retinopathies.

p16 INK4a expression is a robust biomarker of senescence for stem cells in human tissues. Here we examined the effect of exercise intensity on in vivo senescence in skeletal muscle, using a randomized counter-balanced crossover design. Biopsied vastus lateralis of 9 sedentary men (age 26.1 ± 2.5 y) were assessed before and after a single bout of moderate steady state exercise (SSE, 60% maximal aerobic power) and high intensity interval exercise (HIIE, 120% maximal aerobic power) on a cycloergometer accumulating same amount of cycling work (in kilojoule). Increases in cell infiltration (+1.2 folds), DNA strand break (+1.3 folds), and γ-H2AX + myofibers (+1.1 folds) occurred immediately after HIIE and returned to baseline in 24 h ( p < 0.05). Muscle p16 Ink4a mRNA decreased 24 h after HIIE (-57%, p < 0.05). SSE had no effect on cell infiltration, p16 Ink4a mRNA, and DNA strand break in muscle tissues. Senescence-lowering effect of HIIE was particularly prominent in the muscle with high pre-exercise p16INK4a expression, suggesting that exercise intensity determines the level of selection pressure to tissue stem cells at late senescent stage in human skeletal muscle. This evidence provides an explanation for the discrepancy between destructive nature of high intensity exercise and its anti-aging benefits.

Background: Lower gastrointestinal (GI) graft versus host disease (GVHD) represents a severe complication in allogeneic hematopoietic stem cell transplant (HSCT) recipients with high rates of transplant-related mortality. Deregulated innate immunity reactions are the features of its pathogenesis. Cellular senescence has been considered a program of the innate immunity. We focused on lower GI GVHD from the perspective of cellular senescence., Objective: We analyzed the impact of p16 INK4a expression, a hallmark of cellular senescence, in intestinal biopsies of patients with lower GI GVHD symptoms and NFKB1 gene polymorphisms (rs3774937 C/T and rs3774959 A/G) on HSCT outcome., Study Design: Fifty-two single-center patients who presented with symptoms of lower GI GVHD were analyzed in a retrospective manner. Two SNPs located in the NFKB1 gene regions (rs3774937 C/T and rs3774959 A/G) were genotyped from the peripheral blood samples collected before the start of the conditioning. All patients underwent proctosigmoidoscopy with biopsy of the mucosa. The expression of p16 INK4a was analyzed in normal intestinal crypts and stroma., Results: Fifty-two patients (50% male) received HSCT for hematological diseases (acute leukemias in 67%) and developed lower GI symptoms. Patients with p16 INK4a expression in the intestinal stroma were in lower risk of developing histological grade 3-4 aGVHD (RR 0.18 [95% CI 0.05-0.65]; p = 0.009). The multivariate linear regression confirmed the independent effect of p16 INK4a expression on time of the lower GI aGVHD symptoms onset (Coef. 38.9 [95% CI 12.7-65.1]; p = 0.005). The NFKB1 rs3774937 CC and TT/TC genotype were present in 40 and 80% of patients with p16 INK4a expression, respectively (p = 0.04). The rs3774959 AA and GG/AG genotype were present among 43 and 82% of patients with p16 INK4a expression, respectively (p = 0.02). Expression of p16 INK4a was associated with no clinical variable but NFKB1 genotype., Conclusions: Our results address possible new mechanisms that may lead to better understanding of HSCT-related immune complications. Cellular senescence may bring novel approaches in GVHD diagnostics and therapy., Competing Interests: Declaration of Competing Interest The authors have no competing financial interest., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

This study investigated the prevalence of human papillomavirus (HPV) infection in oral squamous cell carcinoma (OSCC) cases, as well as the association between HPV presence and p16 INK4a expression, in Thai patients with OSCC. Eighty-one formalin-fixed paraffin-embedded specimens of OSCC were obtained. DNA extraction was performed; this was followed by nested polymerase chain reaction analysis to determine HPV DNA status, using consensus primers for the L1 region of HPV. HPV subtypes were determined by DNA sequencing. HPV-positive specimens and HPV-negative specimens from age- and sex-matched patients were subjected to immunohistochemical analysis to determine p16 INK4a expression status. Of the 81 OSCC specimens, eight (9.9%) exhibited HPV DNA; DNA sequencing confirmed that the viral subtype was HPV-18 in all eight specimens. These eight HPV-positive specimens, as well as eight HPV-negative specimens from age- and sex-matched patients, were subjected to immunohistochemical analysis to determine p16 INK4a expression status. Three of eight (37.8%) HPV-positive specimens and three of eight (37.8%) HPV-negative specimens showed positive p16 INK4a expression findings. However, we did not find a significant association between HPV status and p16 INK4a expression status in our OSCC samples. In conclusion, the prevalence of high-risk HPV was low in this group of OSCC patients; no association between HPV status and p16 INK4a expression status was identified., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: P16ink4a can accumulate in senescent cells and can be induced by different oncogenic stimulations. These functions make p16ink4a a biomarker of senescence and cancer. However, the exact role of p16ink4a remains unclear in cardiovascular disease. This study was aimed to investigate the role of p16ink4a in cardiac remodeling after myocardial infarction (MI)., Methods: In vivo, gain and loss of function experiments using p16ink4a overexpression and knockdown adenovirus were induced to determine the effect of p16ink4a on cardiac structure and function after MI. The in vitro effects of p16ink4a were evaluated by overexpression and knockdown adenovirus of p16ink4a on isolated neonatal mouse cardiac myocytes (NMCMs) and neonatal mouse cardiac fibroblasts (NMCFs)., Results: Expression level of p16ink4a was increased after MI and enriched in the infarction area. In vivo, overexpression of p16ink4a protected, while knockdown of p16ink4a worsened cardiac function. In vitro, p16ink4a did not influence the hypertrophy of NMCMs. Overexpression of p16ink4a inhibited the proliferation and migration of NMCFs and reduced the level of collagen I and α-SMA. Consistently, knockdown of p16ink4a in vitro displayed the opposite effects. Further mechanism studies revealed that p16ink4a affected the expression level of cyclin-dependent kinase 4 (CDK4) and phosphorylation of retinoblastoma (pRb), which could be a potential pathway in regulating cardiac remodeling after MI., Conclusion: Overexpression of 16ink4a in cardiac fibroblasts can ameliorate cardiac dysfunction and attenuate pathological cardiac remodeling in mice after MI by regulating the p16ink4a/CDK4/pRb pathway., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: The objective of this study was to discover the possible correlation between p16INK4A expression and the LR/HR-HPV infection in condyloma acuminate (CA) lesions., Materials and Method: This cross-sectional study was conducted during January-December 2017 on 33 CA patients. The expression of p16INK4A was detected by immunohistochemistry (IHC) staining. The positive interpretation was carried out by scoring which score 0 was negative, score 1 was sporadic, score 2 was focal, and score 3 was diffuses. The HPV genotypes were identified by reverse line blot, and 40 genotypes of HPV detected, including HR-HPV (HPVs 16, 18, 26, 31, 33,35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 67, 68a, 68b, 69, 73, and 82) and LR-HPV (HPVs 6, 11, 40, 42, 43, 44, 54, 55, 61, 62, 64, 70, 71, 72, 81, 83, 84, 87, 89, and 90)., Results: The expression of p16INK4A was significantly correlated with HR-HPV infection. Patients infected with HR-HPV had 0.644 times higher possibility to express p16INK4A gene compared to those infected with LR-HPV. LR-HPV genotypes detected in CA patients were HPVs 6, 11, 42, 61, 54, 81, 87, 89, and 90 and HR-HPV genotypes were HPVs 18, 26, 45, 51, 52, 67, 68B, 69, and 82. LR-HPV was found in 19/33 of patients and HR-HPV was in 14/33 of patients. The expression of p16INK4A in CA lesions was diffuse in15.2% of patients, was focal in 24.2% of patients , was sporadic in 39.4% of patients were, and was negative in 21.2% of patients . In LR-HPV group, there was no diffuse expression, focal expression was observed in 15.8%, sporadic in 47.4%, and negative in 36.8%, while in HR-HPV group, p16INK4A expression was detected in all lesions , in a way that its expression was diffuse in 35.7%, focal in 35.7%, and sporadic in 28.6%., Conclusion: IHC is a routine method in histopathological diagnosis, therefore the detection of p16INK4A expression by IHC can be used as a biomarker for HR-HPV infection diagnosis.

Background: Cervical cancer screening with cytology suffers from low sensitivity, whereas the efficiency of human papillomavirus (HPV)-based screening is limited by low specificity. The authors evaluated a novel p16 INK4a immunocytology approach in cervical cancer screening compared with HPV-based and cytology-based screening., Methods: In total, 2112 women aged 49 to 69 years from Shanxi, China were screened from March to July 2019. HPV testing, liquid-based cytology (LBC), and p16 INK4a immunocytology were performed on samples from all women. Any positive result triggered a referral to colposcopy with biopsy, if indicated. Screening performance for detecting cervical intraepithelial neoplasia grade 2 and 3 or worse (CIN2+/CIN3+) was evaluated using multiple algorithms., Results: p16 INK4a had a lower positive rate (10.0%) than LBC abnormality (vs 12.1%; P = .004) and a high-risk HPV positivity (21.4%; P < .001). For the detection of CIN3+, the relative sensitivity of p16 INK4a compared with HPV and LBC was 0.93 (95% CI, 0.82-1.07) and 1.12 (95% CI, 0.95-1.32), respectively. The specificity of p16 INK4a was significantly higher than that for HPV and LBC, with a relative specificity of 1.13 (95% CI, 1.11-1.16) and 1.02 (95% CI, 1.01-1.04), respectively. In addition, p16 INK4a alone yielded a clinical performance very similar to that of the current mainstream strategy of using HPV16/18 with reflex cytology (ASC-US+, atypical squamous cells of undetermined significance or worse). The immediate risk of CIN3+ was 14.6% if p16 INK4a results were positive and 0.2% if p16 INK4a results were negative., Conclusions: With minimal colposcopy referrals, p16 INK4a screening demonstrated promising utility for risk stratification and yielded a better balance between sensitivity and specificity compared with HPV and LBC primary screening. Moreover, with accuracy and efficiency similar to what is achieved using mainstream cotest algorithms, p16 may simplify the screening practice. More evidence will be required before clinical recommendation., (© 2021 American Cancer Society.)

T-cell dysfunction arising upon repeated antigen exposure prevents effective immunity and immunotherapy. Using various clinically and physiologically relevant systems, we show that a prominent feature of PD-1-expressing exhausted T cells is the development of cellular senescence features both in vivo and ex vivo . This is associated with p16 INK4a expression and an impaired cell cycle G1 to S-phase transition in repeatedly stimulated T cells. We show that these T cells accumulate DNA damage and activate the p38MAPK signaling pathway, which preferentially leads to p16 INK4a upregulation. However, in highly dysfunctional T cells, p38MAPK inhibition does not restore functionality despite attenuating senescence features. In contrast, p16 INK4a targeting can improve T-cell functionality in exhausted CAR T cells. Collectively, this work provides insights into the development of T-cell dysfunction and identifies T-cell senescence as a potential target in immunotherapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Janelle, Neault, Lebel, De Sousa, Boulet, Durrieu, Carli, Muzac, Lemieux, Labrecque, Melichar, Mallette and Delisle.)

High-grade cervical intraepithelial neoplasia (CIN2 and CIN3) represents a heterogeneous disease with varying cancer progression risks. Biomarkers indicative for a productive human papillomavirus (HPV) infection (HPV E4) and a transforming HPV infection (p16 ink4a , Ki-67 and host-cell DNA methylation) could provide guidance for clinical management in women with high-grade CIN. This study evaluates the cumulative score of immunohistochemical expression of p16 ink4a (Scores 0-3) and Ki-67 (Scores 0-3), referred to as the "immunoscore" (IS), in 262 CIN2 and 235 CIN3 lesions derived from five European cohorts in relation to immunohistochemical HPV E4 expression and FAM19A4/miR124-2 methylation in the corresponding cervical scrape. The immunoscore classification resulted in 30 lesions within IS group 0-2 (6.0%), 151 lesions within IS group 3-4 (30.4%) and 316 lesions within IS group 5-6 (63.6%). E4 expression decreased significantly from CIN2 to CIN3 (P < .001) and with increasing immunoscore group (P trend < .001). Methylation positivity increased significantly from CIN2 to CIN3 (P < .001) and with increasing immunoscore group (P trend < .001). E4 expression was present in 9.8% of CIN3 (23/235) and in 12.0% of IS group 5-6 (38/316). Notably, in a minority (43/497, 8.7%) of high-grade lesions, characteristics of both transforming HPV infection (DNA hypermethylation) and productive HPV infection (E4 expression) were found simultaneously. Next, we stratified all high-grade CIN lesions, based on the presumed cancer progression risk of the biomarkers used, into biomarker profiles. These biomarker profiles, including immunoscore and methylation status, could help the clinician in the decision for immediate treatment or a "wait and see" policy to reduce overtreatment of high-grade CIN lesions., (© 2021 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of Union for International Cancer Control.)

Problem: Cervical cancer screening strategies in the United States include cotesting (human papillomavirus (HPV) with cytology), primary HPV with genotyping and reflex cytology, and cytology alone. An ongoing challenge is the appropriate triage of patients to colposcopy to those at highest risk. We investigated whether incorporation of p16INK4a immunodetection by enzyme-linked immunosorbent assay (ELISA) on fresh cervical samples obtained at the time of screening could improve appropriate referral to colposcopy., Method of Study: A derivation group comprised of cervical swabs collected from subjects with high-grade dysplasia or cancer (positive control) and from subjects with negative screening history (negative control). Samples collected from colposcopy were used to evaluate the existing screening strategies individually and with incorporation of p16INK4a ELISA. Histology was used as the gold standard., Results: Among 163 subjects recruited, 138 were included. In the derivation group, mean p16INK4a level was 2.86 ng/mL (n = 31) and 0.58 ng/mL (n = 20) among positive and negative controls respectively (p = 0.002) with an area under the receiver operator characteristic curve of 0.79 (p < 0.001). Among colposcopy subjects, sensitivity/specificity for cotesting, primary HPV, and cytology were 94%/42%, 88%/45%, and 88%/49%, respectively. Incorporation of p16INK4a resulted in similar sensitivity and improved specificity (cotesting+p16 88%/58%, primary HPV+p16 88%/57%, cytology+p16 81%/62%; p = 0.23/p = 0.008) with decrease in colposcopy referrals by 15% to 22% (p = 0.01)., Conclusions: These results demonstrate the feasibility of quantifying p16INK4a by ELISA in fresh cervical samples, and its potential as an adjunct to existing screening strategies in the identification of high grade-dysplasia while reducing the number of colposcopic referrals., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The Cdkn2a locus is one of the most studied tumor suppressor loci in the context of several cancer types. However, in the last years, its expression has also been linked to terminal differentiation and the activation of the senescence program in different cellular subtypes. Knock-out (KO) of the entire locus enhances the capability of stem cells to proliferate in some tissues and respond to severe physiological and non-physiological damages in different organs, including the heart. Emery-Dreifuss muscular dystrophy (EDMD) is characterized by severe contractures and muscle loss at the level of skeletal muscles of the elbows, ankles and neck, and by dilated cardiomyopathy. We have recently demonstrated, using the LMNA Δ 8-11 murine model of Emery-Dreifuss muscular dystrophy (EDMD), that dystrophic muscle stem cells prematurely express non-lineage-specific genes early on during postnatal growth, leading to rapid exhaustion of the muscle stem cell pool. Knock-out of the Cdkn2a locus in EDMD dystrophic mice partially restores muscle stem cell properties. In the present study, we describe the cardiac phenotype of the LMNA Δ 8-11 mouse model and functionally characterize the effects of KO of the Cdkn2a locus on heart functions and life expectancy.

High-risk human papillomaviruses (hr-HPVs) are the key risk factors implicated in the development of a significant proportion of head and neck squamous cell carcinomas (HNSCCs). We aimed to investigate the distribution of hr-HPV types and HPV16 lineages in a sample of patients with HNSCC and the possible association between HPV status and the expression of P16INK4A and NF-κB in Iranian HNSCC patients. We examined 108 formalin-fixed, paraffin-embedded (FFPE) histologically confirmed primary SCC tissue specimens of different head and neck anatomical sites. HPV types and HPV16 lineages were determined by nested PCR and overlapping nested PCR assays, respectively, followed by gene sequencing and phylogenetic analysis. The expression of p16INK4a and NF-κB was evaluated by immunohistochemistry. Twenty-five (23.1%) HNSCC tissue specimens were tested positive for HPV infection. The most prevalent HPV type was HPV-16, followed by HPV18 and HPV11. HPV16 variants belonged to the lineage A and lineage D which were further sorted into sublineages A1, A2, and D2. A significant association between HPV status and p16INK4a immunoreactivity was observed in more than 76% of the HPV-related HNSCCs (P < 0.0001). The overexpression of p16INK4a and cytoplasmic NF-κB was more common in low-grade HNSCC tumors. Our data highlights that HPV16, in particular the A2 sublineage, followed by A1 and D2 sublineages are the major agents associated with HNSCCs in Iran. Based on HPV16 predominance and its lineage distribution pattern, it seems that the prophylactic vaccines developed for cervical cancer prevention could also be applicable for the prevention of HPV-related HNSCCs in our population.

Background: To improve the efficiency of early diagnosis systems for cervical cancer, the use of cellular and viral markers for identifying precancerous lesions with a greater probability to progress to cancer has been proposed. Several cellular proteins and markers of oxidative DNA damage have been suggested as possible biomarkers of cervical carcinogenesis; however, they have not been evaluated together. In this study, we analyzed the expression of the cellular markers p16 INK4a , Ki-67, CyclinE1, TOP2A/MCM2, and telomerase, as well as the DNA oxidative damage markers ROS and 8-OHdG. The analyses were performed in liquid-based cervical cytology samples or biopsies with premalignant lesions or cervical cancer diagnosis, with the purpose of selecting a panel of biomarkers that allow the identification of precursor lesions with greater risk of progression to cervical cancer., Methods: We analyzed 1485 liquid-based cytology samples, including 239 non-squamous intraepithelial lesions (NSIL), 901 low-grade squamous intraepithelial lesions (LSIL), 54 high-grade squamous intraepithelial lesions (HSIL), and 291 cervical cancers (CC). The biomarkers were analyzed by immunocytochemistry and Human Papilloma Virus (HPV) genotyping with the INNO-LiPA genotyping Extra kit., Results: We found that all tested cellular biomarkers were overexpressed in samples with high risk-HPV infection, and the expression levels increased with the severity of the lesion. TOP2A/MCM2 was the best biomarker for discriminating between LSIL and HSIL, followed by p16 INK4a and cyclinE1. Statistical analysis showed that TOP2A/MCM2 provided the largest explanation of HSIL and CC cases (93.8%), followed by p16 INK4a (91%), cyclin E1 (91%), Ki-67 (89.3%), and telomerase (88.9%)., Conclusions: We propose that the detection of TOP2A/MCM2, p16 INK4a and cyclin E1 expression levels is useful as a panel of biomarkers that allow identification of cervical lesions with a higher risk for progression to CC with high sensitivity and precision; this can be done inexpensively, in a single and non-invasive liquid-based cytology sample.

The proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) are involved in the corneal inflammatory response and wound healing following corneal injuries. However, the mechanism by which proinflammatory cytokines modulate corneal epithelial wound healing remains unclear. In this study, we found that IL-1β or TNF-α was transiently elevated during corneal epithelial wound healing in mice. After corneal epithelial debridement, persistent treatment with IL-1β or TNF-α restrained the level of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) and boosted the level of cell cycle inhibitor p16 Ink4a , resulting in impaired corneal epithelial repair. When p16 Ink4a was deleted, the p-STAT3 level in corneal epithelium was enhanced and corneal epithelial wound healing was clearly accelerated. In diabetic mice, IL-1β, TNF-α, and p16 Ink4a appeared a sustained and strong expression in the corneal epithelium, and p16 Ink4a knockdown partially reverted the defective diabetic corneal epithelial repair. Furthermore, immunoprecipitation proved that p16 Ink4a interacted with p-STAT3 and thus possibly suppressed the STAT3 activity. Our findings revealed a novel mechanism that the proinflammatory cytokines modulate corneal epithelial wound healing via the p16 Ink4a -STAT3 signaling., (© 2020 Wiley Periodicals LLC.)

Cell senescence plays a key role in age-associated organ dysfunction, but the in vivo pathogenesis is largely unclear. Here, we generated a p16-Cre ERT2 -tdTomato mouse model to analyze the in vivo characteristics of p16 high cells at a single-cell level. We found tdTomato-positive p16 high cells detectable in all organs, which were enriched with age. We also found that these cells failed to proliferate and had half-lives ranging from 2.6 to 4.2 months, depending on the tissue examined. Single-cell transcriptomics in the liver and kidneys revealed that p16 high cells were present in various cell types, though most dominant in hepatic endothelium and in renal proximal and distal tubule epithelia, and that these cells exhibited heterogeneous senescence-associated phenotypes. Further, elimination of p16 high cells ameliorated nonalcoholic steatohepatitis-related hepatic lipidosis and immune cell infiltration. Our new mouse model and single-cell analysis provide a powerful resource to enable the discovery of previously unidentified senescence functions in vivo., Competing Interests: Declaration of Interests The authors declare that they have no conflicts of interest with respect to the contents of this article. RIKEN has filed patents of CUBIC reagents in which E.A.S. and H.R.U. are co-inventors. Part of this study was performed in collaboration with Olympus Corporation., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To evaluate the effect of Guilu Erxian Glue (, GEG) on cyclophosphamide (CTX)-induced bone marrow hematopoietic stem cells (HSCs) senescence in mice and explore the underlying mechanism., Methods: The H 22 liver cancer ascites lump model was established in male Kunming mice by injecting intraperitoneally (i.p.) with 5 × 10 6 /mL H 22 cells per mouse. Fifty tumor-bearing mice were divided into the control, model, pifithrin-α, GEG, and GEG+pifithrin-α groups using a random number table, 10 mice in each group. CTX (100 mg/kg i.p.) was administrated to mice from day 1 to day 3 (d1-d3) continuously except for the control group. The mice in the pifithrin-α, GEG and GEG+pifithrin-α groups were treated with pifithrin-α (2.2 mg/(kg·d) i.p.) for 6 consecutive days (d4-d9), GEG (9.5 g/(kg·d) i.p.) for 9 consecutive days (d1-d9), and GEG plus pifithrin-α, respectively. HSCs were collected after 9-d drug treatment. The anti-aging effect of GEG was studied by cell viability, cell cycle, and β -galactosidase (β -gal) assays. The mRNA and protein expressions of cyclin-dependent kinase 2 (CDK2), CDK4, inhibitor of cyclin-dependent kinase 4a encoding the tumor suppressor protein p16 (p16 INK4a ), p21 Cip1/Waf1 , p53, and phosphorylated retinoblastoma (pRb) were evaluated by quantitative real-time reverse transcription-polymerase chain reaction and semi-quantitative Western blot, respectively., Results: Compared with the model group, GEG increased cell viability as well as proliferation (P<0.05 or P<0.01) and reduced β -gal expression. Furthermore, GEG significantly decreased the expressions of p16 INK4a , p53 and p21 Cip1/Waf1 proteins, and increased the expressions of CDK2, CDK4 and pRb proteins compared with the model group (P<0.05 or P<0.01)., Conclusion: GEG can alleviate CTX-induced HSCs senescence in mice, and the p16 INK4a -Rb signaling pathway might be the underlying mechanism.

Genetic alterations in the INK4a/ARF (or CDKN2A ) locus have been reported in many cancer types, including melanoma; head and neck squamous cell carcinomas; lung, breast, and pancreatic cancers. In melanoma, loss of function CDKN2A alterations have been identified in approximately 50% of primary melanomas, in over 75% of metastatic melanomas, and in the germline of 40% of families with a predisposition to cutaneous melanoma. The CDKN2A locus encodes two critical tumor suppressor proteins, the cyclin-dependent kinase inhibitor p16 INK4a and the p53 regulator p14 ARF . The majority of CDKN2A alterations in melanoma selectively target p16 INK4a or affect the coding sequence of both p16 INK4a and p14 ARF . There is also a subset of less common somatic and germline INK4a/ARF alterations that affect p14 ARF , while not altering the syntenic p16 INK4a coding regions. In this review, we describe the frequency and types of somatic alterations affecting the CDKN2A locus in melanoma and germline CDKN2A alterations in familial melanoma, and their functional consequences in melanoma development. We discuss the clinical implications of CDKN2A inactivating alterations and their influence on treatment response and resistance.

Objective: To investigate the prevalence of human papillomavirus (HPV) in archival head and neck cancer (HNC) collected from the Tong-Liao area, which is located in east Inner Mongolia, China., Methods: The presence of HPV in 54 HNCs and 25 benign biopsies was detected and the sequence variation of the E6 gene in HPV-positive samples was analyzed to determine their lineage/sublineage classification., Results: HPV was detected in only 4 out of 54 HNCs and no benign biopsies were found to be HPV-positive. After further p16 INK4a immunostaining, only 3 cases of HNC were positive for both HPV and p16 INK4a . Phylogenetic analysis of the isolated E6 gene shows that the HPV 16, HPV 31, and HPV 58 isolated in this study belong to lineage A., Conclusions: The prevalence of HPV in HNC from this area is very low. The lineage/sublineage classification of the 3 HPV types in HNC in this area is consistent with the previous reported data of HPV lineage distribution in cervical cancer within China.

Background: Cytotoxic chemotherapy can cure advanced germ cell tumors. Nevertheless, cancer treatment may induce cellular senescence and accelerate molecular aging. The aging process implies an increase of cells expressing p16 INK4a and changes in lymphocyte subpopulations. Our aim was to study the potential induction of premature immunosenescence in testicular cancer survivors (TCS) exposed to chemotherapy., Methods: Case-control exploratory study of TCS treated with chemotherapy (≥3 BEP cycles, disease-free ≥3 months) compared with age matched healthy controls. Peripheral blood mononuclear cells were isolated, and lymphocyte subpopulations were analyzed by flow cytometry. CDKN2A/p16 INK4a expression in T cells was measured using qPCR. The percentage of lymphocyte subpopulations and the CDKN2A/p16 INK4a expression in TCS were compared with the control group using the Wilcoxon signed-rank test., Results: We included 16 cases and 16 controls. The median age was 27 years (minimum 24, maximum 54) and the median time on surveillance was 26.5 months (minimum 3, maximum192). TCS had a lower percentage of total T cells and CD4+ T cells in total lymphocytes. Among the CD4+ T lymphocytes, TCS had less naïve CD4+ and increased memory CD4+ cells. Within the CD8+ T lymphocytes, TCS exhibited a decrease in the percentage of naïve cells and an increase in CD8 + CD45RA + CD57+ cells. TCS also exhibited decreased memory CD19+ B cells compared to the controls. The relative expression of CDKN2A/p16 INK4a in T cells was increased in TCS (mean 1.54; 95% CI of the mean: 1.074-2.005; p = 0.048)., Conclusion: In this exploratory study, TCS showed increased expression of CDKN2A/p16 INK4a and a lymphocyte phenotype that has been associated with immunosenescence. Further studies are warranted to define the clinical implications of these alterations in TCS.

The Hsp90 chaperone has become the attractive pharmacological target to inhibit tumor cell proliferation. However, tumor cells can evolve with mechanisms to overcome Hsp90 inhibition. Using human neuroblastoma, we have investigated one such limitation. Here, we demonstrate that neuroblastoma cells overcome the interference of tumor suppressor p16 INK4a in cell proliferation, which is due to its latent interaction with CDK4 and CDK6. Cells also displayed impedance to the pharmacological inhibition of cancer chaperone Hsp90 inhibition with respect to induced cytotoxicity. However, the p16 INK4a knockdown has triggered the activation of cyclin-CDK6 axis and enhanced the cell proliferation. These cells are eventually sensitized to Hsp90 inhibition by activating the DNA damage response mediated through p53-p21 WAF-1 axis and G1 cell cycle exit. While both CDK4 and CDK6 have exhibited low affinity to p16 INK4a , CDK6 has exhibited high affinity to Hsp90. Destabilizing the CDK6 interaction with Hsp90 has prolonged G2/M cell cycle arrest fostering to premature cellular senescence. The senescence driven cells exhibited compromised metastatic potential both in vitro as well as in mice xenografts. Our study unravels that cancer cells can be adapted to the constitutive expression of tumor suppressors to overcome therapeutic interventions. Our findings display potential implication of Hsp90 inhibitors to overcome such adaptations., (© 2019 Wiley Periodicals, Inc.)

Bronchiolar adenoma (BA) of the lung is a rare benign neoplasm. Because of a chest abnormal shadow indicated by health checkup, a 77-year-old female nonsmoker underwent computed tomography, revealing an 8 mm ground glass nodule in the peripheral field of the right lower lobe. Wedge resection of the nodule was performed, with a frozen diagnosis of primary lung adenocarcinoma. The localized, 8 × 4 × 3 mm-sized, jelly-like mass microscopically revealed a lepidic-growing lesion composed of ciliated columnar cells, mucous cells and basal cells surrounded by mucin pool. Neither nuclear atypia nor mitotic activity was noted. Immunohistochemically, the ciliated, mucous and basal cells were positive for TTF-1 and p16 INK4a . Mucous cells were positive for napsin A and focally expressed MUC5AC. MUC6 was negative. Basal cells were positive for CK5/6, p40, p63 and podoplanin. Human papillomavirus genome was undetectable by in situ hybridization. Ultrastructurally, the bronchiolar epithelial tubules consisted of two layers, the inner nonciliated microvillous cells and the outer basal-like cells, and some of the inner cells were filled with mucin granules in cytoplasm. Molecular analysis of the tumor failed to show driver mutations. The final diagnosis was distal-type BA. The postoperative course was uneventful for 6 months., (© 2020 The Authors. Pathology International published by Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

Purpose: To evaluate HPV and p16 ink4a status as prognostic factors in patients with invasive vulvar cancer., Methods: Retrospective analysis of disease-free (DFS) and disease-specific survival (DSS) of patients with invasive vulvar cancer at a single tertiary care center. Histology, HPV and p16 ink4a status were evaluated in the context of a global multicenter trial. Logistic regression models were performed to identify the impact of p16 ink4a positivity., Results: 135 patients were included in the analysis. 32 (23.7%) showed a p16 ink4a expression of over 25%. Disease-free and disease-specific survival was longer in p16 ink4a positive patients (23 vs. 10 months, p = 0.004, respectively, 29 vs. 21 months, p = 0.016). In multivariate analysis, p16 ink4a positivity was an independent parameter for DFS (p = 0.025, HR: 2.120 (1.100-4.085)), but not for DSS (p = 0.926, HR: 1.029 (0.558-1.901), in contrast to age and tumor stage., Conclusions: Age and tumor stage negatively affect survival. However, disease-free survival is significantly longer in patients with p16 ink4a positive invasive vulvar cancer.

As p53-binding protein 1 (53BP1) localizes to the sites of DNA double-strand breaks and rapidly forms nuclear foci (NF), and its presence may be an indicator of endogenous genomic instability (GIN). We previously showed that 53BP1 NF in cervical cells increase with neoplastic progression, indicating the significance of 53BP1 expression for the estimation of malignant potential during cervical carcinogenesis. This study aimed to further elucidate the impact of 53BP1 expression as a biomarker for cervical squamous intraepithelial lesion (SIL). A total of 81 tissue samples, including 17 of normal cervical epithelium, 22 of cervical intraepithelial neoplasia (CIN) 1, 21 of CIN2, and 21 of CIN3, from patients positive for high-risk human papillomavirus (HR-HPV) were used for double-label immunofluorescence of 53BP1 and Ki-67/p16 INK4a expression and HR-HPV in situ hybridization. We analyzed associations between 53BP1 expression type with parameters such as CIN grade, HR-HPV infection status, p16 INK4a expression, and CIN prognosis. Expression type of 53BP1 was significantly associated with histological grade of CIN and HR-HPV in situ hybridization signal pattern ( P < .0001). There was a significant correlation between 53BP1 and p16 INK4a expression levels ( r = .73, P < .0001). However, there was no association between 53BP1 expression type and CIN prognosis. We propose that 53BP1 expression type is a valuable biomarker for SIL, which can help estimate the grade and GIN of cervical lesions reflecting replication stress caused by the integration of HR-HPV to the host genome.

Background: Hormone-receptor-negative breast carcinoma (HRNBC), including triple-negative and HER-2 amplified tumors, can overexpress P16INK4a with substantial contribution to tumor progression. In nonneoplastic cells, P16INK4a mediates growth arrest and senescence secondary to cytotoxic compounds., Objective: We assessed the impact of neoadjuvant chemotherapy (NAC) on P16INK4a expression in breast specimens., Methods: P16INK4a and CD-44 were evaluated by immunohistochemistry in biopsies and subsequent post-NAC excision in a cohort of 27 women with HRNBC. Positivity was estimated on hotspots of tissue available by calculating cellular densities in nonneoplastic tissues with a low proliferation rate (Ki-67 < 1%) and tumor percentage using ImageJ 1.51t (National Institutes of Health, USA)., Results: Pre-NAC P16INK4a and CD-44 tumor expression were similar between the complete (n = 15) and incomplete (n = 12) response groups. Residual HRNBCs exhibited decreased immunoreactivity for P16INK4a, while the expression of CD-44 increased (n = 10, P < 0.05). The magnitude of change correlated with the baseline expression (r = 0.37, P16; r = -0.85, CD-44). Post-NAC nonneoplastic mammary duct and lobular epithelia, perilobular stroma, and adipose tissue, but not peritumoral stroma, accumulated P16INK4a(+) cells. The post-NAC cellular density change was more significant in epithelia of patients with high P16INK4a(+) baseline (r = 0.86, P < 0.0001) and those with a complete pathologic response (n = 14, P < 0.05). All tumors beds with complete treatment effect showed diffuse P16INK4a positivity., Conclusion: NAC induced the accumulation of P16INK4a(+)cells in nonneoplastic breast tissues more pronounced in patients with a complete pathologic response. Therapy-induced senescence is a potential marker of bystander damage due to NAC. P16INK4a loss and CD-44 gain may represent a phenotype of chemoresistance in residual HRNBCs.

Background: Approximately 50% of cases of penile carcinoma (PeCa), a rare neoplasm worldwide, are associated with human papillomavirus (HPV). However, the detection of HPV-DNA is not sufficient to consider it the etiological factor in the development of this type of cancer. Currently, the overexpression of P16INK4A is used as a surrogate biomarker of HPV carcinogenesis. Information on PeCa in Mexico is scarce, particularly regarding cases related to HPV and genotype frequency., Objective: To evaluate the presence of HPV, its genotypes, and the presence of multiple genotypes, and the expression of P16INK4A, as well as its clinical and histopathological parameters., Methods: For HPV-DNA detection and P16INK4A expression, we used the INNO-LiPA® test and immunohistochemistry, respectively., Results: Sixty cases of PeCa were evaluated, of which 75% were HPV-non-related histological variants. We found that 58.9% (33/56) of PeCa cases were HPV-DNA positive, while 30.9% of the cases evaluated (17/55) were positive for P16INK4A. HPV16 was the main genotype in 42.9% of the cases, followed by HPV52 in 7.1% and HPV18 in 5.4%. Within the HPV-positive cases, 27.3% had multiple genotypes. All HPV-positive patients under the age of 45 years were positive only for HPV16., Conclusions: HPV16 was the most commonly detected genotype in PeCa. HPV 31, 35 and 39 were infrequent; however, they were related to a single infection and P16INK4A overexpression; thus, they seem to be relevant in PeCa carcinogenesis. Our results suggest that P16INK4A overexpression could be useful for the classification of HPV-related PeCa. The role of multiple HPV genotypes in the development and prognosis of PeCa is still not completely understood. Thus, it is necessary to define criteria to establish reliable ways to classify HPV-related PeCa that could lead to optimal therapeutic approaches.

The role of cyclin-dependent kinase inhibitor 2A gene (CDKN2A) variants in breast cancer is not well understood, here we investigated their possible effects on breast cancer in Pakistani women attending the NORI Hospital, Islamabad. Direct DNA sequencing of CDKN2A identified an already known polymorphism in the 3' UTR, c.*29G>C (rs11515), in 5.88% patients and two novel variants. One, a deep intronic substitution (c.458-554T>G) in 1.96% patients, is also detected as a compound heterozygous form along with c.*29G>C in 1.96% patients (c.[458-554T>G; *29G>C]). The other is a novel deletion (c.458-82delG) occurring as a compound variant with two other identified variants c.[458-554T>G; 458-82delG; *29G>C] in 1.96% patients. In silico pathogenicity prediction analyses did not predict pathogenic effects on breast cancer for these individual variants. We conclude that variations in CDKN2A are not the major genetic cause of breast cancer in the enrolled Pakistani patients.

Rationale: Age-related changes in the intervertebral discs are the predominant contributors to back pain, a common physical and functional impairment experienced by older persons. Cellular senescence, a process wherein cells undergo growth arrest and chronically secrete numerous inflammatory molecules and proteases, has been reported to cause decline in the health and function of multiple tissues with age. Although senescent cells have been reported to increase in intervertebral degeneration (IDD), it is not known whether they are causative in age-related IDD., Objective: The study aimed to elucidate whether a causal relationship exists between cellular senescence and age-related IDD., Methods and Results: To examine the impact of senescent cells on age-associated IDD, we used p16-3MR transgenic mice, which enables the selective removal of p16 Ink4a -positive senescent cells by the drug ganciclovir. Disc cellularity, aggrecan content and fragmentation alongside expression of inflammatory cytokine (IL-6) and matrix proteases (ADAMTS4 and MMP13) in discs of p16-3MR mice treated with GCV and untreated controls were assessed. In aged mice, reducing the per cent of senescent cells decreased disc aggrecan proteolytic degradation and increased overall proteoglycan matrix content along with improved histological disc features. Additionally, reduction of senescent cells lowered the levels of MMP13, which is purported to promote disc degenerative changes during aging., Conclusions: The findings of this study suggest that systemic reduction in the number of senescent cells ameliorates multiple age-associated changes within the disc tissue. Cellular senescence could therefore serve as a therapeutic target to restore the health of disc tissue that deteriorates with age., (© 2019 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.)

We previously reported that the canonical innate immune receptor toll-like receptor 4 (TLR4) is critical in maintaining lung integrity. However, the molecular mechanisms via which TLR4 mediates its effect remained unclear. In the present study, we identified distinct contributions of lung endothelial cells (Ec) and epithelial cells TLR4 to pulmonary homeostasis using genetic-specific, lung- and cell-targeted in vivo methods. Emphysema was significantly prevented via the reconstituting of human TLR4 expression in the lung Ec of TLR4-/- mice. Lung Ec-silencing of TLR4 in wild-type mice induced emphysema, highlighting the specific and distinct role of Ec-expressed TLR4 in maintaining lung integrity. We also identified a previously unrecognized role of TLR4 in preventing expression of p16 INK4a , a senescence-associated gene. Lung Ec-p16 INK4a -silencing prevented TLR4-/- induced emphysema, revealing a new functional role for p16 INK4a in lungs. TLR4 suppressed endogenous p16 INK4a expression via HDAC2-mediated deacetylation of histone H4. These findings suggest a novel role for TLR4 in maintaining of lung homeostasis via epigenetic regulation of senescence-related gene expression., (© 2019 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.)

Background: Liquid based cytology with dual biomarkers has improved sensitivity and specificity in detecting high grade cervical intraepithelial neoplasia (CIN). In low resource settings, especially in organized camps, LBC is costly and immunohistochemistry on conventional pap smears is difficult to standardize with consumption of lots of reagents. In present study, to improve the accuracy of conventional pap smears and reduce the cost of biomarker testing, we evaluated conventional cell blocks (CCBs) preparations with biomarkers to detect high-grade CIN in resource-poor organized screening programs. We also studied feasibility of using CCB as primary screening test. Material and Methods: A total of 350 participants were included in the cross-sectional evaluation of the screening tests. A conventional Papanicolaou (Pap) smear was obtained, and another sample was then collected and placed in 10% neutral buffered formalin for CB preparation. All abnormal Pap tests and CBs were stained for the biomarkers p16INK4a and Ki67. Histopathology with p16INK4a expression was considered the gold standard. Diagnostic tests were compared using MacNemar’s test and receiver operating curves were plotted. Results: The sensitivity, specificity, and diagnostic accuracy of CCB cytology, CB + p16 cytology and CB + p16Ki67 cytology for detecting CIN2+ lesions were 85.71%, 100%, 97.44%; 100%, 93.75%, 94.87%; and 85.71%, 100%, 97.44%, respectively. The Ki67 index could further categorize low grade lesions into lesions with low proliferative index and with high proliferative index (Pearson chi-square p value <0.001). Conclusion: If CB preparation is standardized, CCB cytology with biomarkers can have better diagnostic accuracy than conventional cytology, can classify low grade lesions likely to progress and can be used in field settings as primary screening test., (Creative Commons Attribution License)

Background: Women with atypical squamous cells of undetermined significance (ASC-US) can be triaged accurately with a high-risk human papillomavirus (hrHPV) test to identify those who need a referral. However, the triage of low-grade squamous intraepithelial lesion (LSIL) with hrHPV testing has very low specificity. Overexpression of p16, with or without Ki-67, indicates neoplastic transformation of human papillomavirus-infected cervical cells and may more accurately predict underlying cervical intraepithelial neoplasia of grade 3 or worse (CIN3+)., Methods: A literature search was conducted in 3 bibliographic databases. Studies were selected if they included women with ASC-US or LSIL who were triaged with dual staining (p16/Ki-67) and/or p16 staining and, if available, with a comparator hrHPV test to detect cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) or CIN3+., Results: Thirty-eight studies were eligible. The sensitivity of p16 staining for CIN3+ was significantly lower than that of hrHPV DNA testing (ratio for ASC-US, 0.87; 95% confidence interval [CI], 0.78-0.97; ratio for LSIL, 0.86; 95% CI, 0.80-0.93). In contrast, the specificity of p16 staining was substantially higher with relative specificities of 1.60 (95% CI, 1.35-1.88) and 2.29 (95% CI, 2.05-2.56) for ASC-US and LSIL respectively. Dual staining was as sensitive as hrHPV DNA testing but was more specific (ratio for ASC-US, 1.65; 95% CI, 1.42-1.92; ratio for LSIL, 2.45; 95% CI, 2.17-2.77)., Conclusions: This meta-analysis confirms that p16 staining and p16/Ki-67 staining are more specific for CIN2+/CIN3+ than hrHPV DNA testing. Although p16 staining is less sensitive for CIN3+ than hrHPV DNA testing, dual staining has similar sensitivity., (© 2019 American Cancer Society.)

Down-regulation of p16INK4a and miR-146b-5p contributes to tumorigenesis in osteosarcoma (OS). However, the correlation between p16INK4a and miR-146b-5p in OS proliferation remains largely unknown. In the present study, we demonstrated that miR-146b-5p expression was positively correlated with p16INK4a in OS, but inversely correlated with TNF receptor associated factor 6 (TRAF6) expression. Overexpression of miR-146b-5p dramatically suppressed OS cell proliferation. Mechanistically, we validated TRAF6 as a direct functional target of miR-146b-5p and found that miR-146b-5p overexpression significantly decreased the level of phosphorylated PI3k and Akt, which are the pivotal downstream effectors of TRAF6. Moreover, TRAF6 expression was positively correlated with Ki-67 but inversely correlated with miR-146b-5p expression. In OS cells, silencing of TRAF6 mimicked the anti-tumor effects of miR-146b-5p. p16INK4a is an important tumor suppressor gene frequently down-regulated in OS. We found that this inhibitory effect is associated with the suppression of the miR-146b-5p, and is mediated via up-regulating TRAF6 expression. Our findings identified p16INK4a and miR-146b-5p as tumor suppressors, and suggested p16INK4a, miR-146b-5p and TRAF6 as potential therapeutic candidates for malignant OS., (© 2019 The Author(s).)

Background: Cartilage degradation would result in osteoarthritis (OA). p16INK4awas found in some age-related diseases. In this study, we aimed to determine the role of p16INK4a during OA and to investigate the underlying mechanisms., Methods: Enzyme-linked immunosorbent assay (ELISA) was performed to test the activity of senescence-associated secretory phenotype (SASP). Real-time PCR (RT-PCR) and Western blot were used to determine the expressions of target genes., Results: The increased expressions of p16INK4a and E2F2 were accompanied with cartilage degradation induced by IL-1β. Over-expression of p16INK4a enhanced the secretion of SASP markers (TGFβ, IL-6, IL-8, IL-1α, MMP3 and MMP13), reduced the expression of type II procollagen (COL2A1).Thus, the over-expression of p16INK4a lead to cartilage injury. Moreover, we found that the expression of E2F2 was enhanced in p16INK4a over-expression group, and that cartilage injury caused by p16INK4a was alleviated by depleting E2F2., Conclusions: p16INK4a was up-regulated during the cartilage injury in OA. p16INK4a promoted cartilage injury by increasing the expression of E2F2. Thus, this study extends the molecular regulation network for understanding pathological progression of OA, and provides potential therapeutic target for OA.

Previous studies have suggested that cancer stem cells (CSCs) resisted radiotherapy and chemotherapy. P16 INK4A is a biomarker for cervical carcinogenesis and reduces proliferation of stem cells. We aimed to investigate the expression and clinical significance of cyclin-dependent kinase inhibitor 2A (P16 INK4A ), sex determining region Y-box 2 (SOX2), and Aldehyde dehydrogenase 1 family, member A1 (ALDH1A1) in cervical cancer treated with radiotherapy and cervical cell line models. The expressions of P16 INK4A , SOX2, and ALDH1A1 were performed by immunohistochemical staining of tumor samples from 139 cervical cancer patients with International Federation of Gynecology and Obstetrics stages Ib to IV. The staining showed high expression in 100, 107, and 13 patients with P16 INK4A (>80%), SOX2 (≥10%), and ALDH1A1 (50%), respectively. The high-P16 INK4A group had a higher five-year overall survival (OS) rate and disease-free survival (DFS) than the low-P16 INK4A group (OS: 62.0% and 35.2%, p = 0.016; DFS: 60.0% and 31.2%, p = 0.002). The low-P16 INK4A /high-SOX2 and low-P16 INK4A /high-ALDH1A1 groups had a worse five-year OS and DFS rate than the high-P16 INK4A /low-SOX2 and high-P16 INK4A /low-ALDH1A1 groups, respectively. Depletion of P16 INK4A promoted chemoresistance and radioresistance of cervical cancer cells increased the expression of SOX2 and ALDH1A1 and exhibited higher self-renewal ability. These results suggest that lower P16 INK4A expression associated with higher CSC markers predicts poor prognostic outcomes and is a promising target in patients with cervical cancer.

Autologous human cardiac stem/progenitor cell (hCPC) therapy is a promising treatment that has come into use in recent years for patients with cardiomyopathy. Though innovative in theory, a major hindrance to the practical application of this treatment is that the hCPCs of elderly patients, who are most susceptible to myocardial disease, are senescent and prone to cell death. Rejuvenating hCPCs from elderly patients may help overcome this obstacle, and can be accomplished by reversing entry into the cellular stage of senescence. p16 INK4A , a cyclin dependent kinase inhibitor, is an important player in the regulation of cell senescence. In this study, we investigated whether knockdown of p16 INK4A will rejuvenate aging hCPCs to a youthful phenotype. Our data indicated that upregulation of p16 INK4A is associated with hCPC senescence. Both cell proliferation and survival capacity were significantly increased in hCPCs infected with lentivirus expressing p16 INK4A shRNA when compared to control hCPCs. The knockdown of p16 INK4A also induced antioxidant properties as indicated by a 50% decrease in ROS generation at basal cell metabolism, and a 25% decrease in ROS generation after exposure to oxidative stress. Genes associated with cell senescence (p21 CIP1 ), anti-apoptosis (BCL2 and MCL1), anti-oxidant (CYGB, PRDX1 and SRXN1), and NFκB signal pathway (p65, IKBKB, HMOX1, etc.), were significantly upregulated after the p16 INK4A knockdown. Knocking down the NFĸB-p65 expression also significantly diminished the cytoprotective effect caused by the p16 INK4A knockdown. Our results suggest that genetic knockdown of p16 INK4A may play a significant role in inducing antioxidant effects and extending lifespan of aging hCPCs. This genetic modification may enhance the effectiveness of autologous hCPC therapy for repair of infarcted myocardium.

Aims: Cellular senescence plays a role in tumour suppression and in the pathogenesis of various non-neoplastic diseases, including primary biliary cholangitis and other adult cholangiopathies. Less is known about the role of cellular senescence in cholangiopathies in children. With that in mind, we examined the expression of senescence-associated cell cycle regulators in biliary atresia, the most common form of paediatric obliterative cholangiopathy., Methods and Results: The expression of senescence-associated cell cycle regulators (p16 Ink4a and p21 WAF 1/Cip1 ) and a ductular reaction related marker (neural cell adhesion molecule: NCAM) was examined in bile ducts and bile ductules in liver samples taken from the patients with biliary atresia [n = 80; including 23 samples at the time of the Kasai procedure (KP) and 63 obtained from the explanted liver (LT) (six cases with samples at both surgical stages of disease)] and from appropriate controls (n = 17). The degree of ductular reaction and cholestasis was significantly more extensive in LT than KP (P < 0.01). The expression of p16 INK 4a and NCAM was significantly more extensive in bile ducts and bile ductules in ductular reaction in both KP and LT compared to controls and in LT compared to KP (P < 0.05). The expression of p21 WAF 1/Cip1 was significantly more extensive in bile ducts and bile ductules in KP compared to both LT and controls (P < 0.01)., Conclusions: Cellular senescence may play a role in the progression of bile duct loss in biliary atresia in a manner similar to that of adult cholangiopathies., (© 2018 John Wiley & Sons Ltd.)

Human papillomavirus (HPV) E2 and L1 proteins are expressed in cervical cells during the lytic stage of infection. Overexpression of p16 INK4A is a biomarker of HPV-associated cervical neoplasia. This study investigated antibodies to HPV16 E2, HPV16 L1, and p16 INK4A in sera from women with no squamous intraepithelial lesion (No-SIL) of the cervix, low-grade SIL, high-grade SIL, and cervical squamous cell carcinoma (SCC). HPV DNA was detected by polymerase chain reaction. Anti-E2, -L1, and -p16 INK4A antibodies in sera were determined by western blot. Among 116 samples, 69 (60%) were HPV DNA-positive. Percentages seropositive for anti-E2, -L1, and -p16 INK4A antibodies were 39.6, 22.4, and 23.3%, respectively. Anti-E2 antibody was significantly correlated with HPV DNA-positive cases. Eighty-seven women (75%) were regarded as infected with HPV, having at least one positive result from HPV DNA, L1, or E2 antibody. Antibody to p16 INK4A was associated with HPV infection (odds = 5.444, 95% CI 1.203-24.629, P = 0.028) and precancerous cervical lesions (odds = 5.132, 95% CI 1.604-16.415, P = 0.006). Interestingly, the concurrent detection of anti-E2 and -p16 INK4A antibodies was significantly associated with HPV infection (odds = 1.382, 95% CI 1.228-1.555, P = 0.044). These antibodies might be good candidate biomarkers for monitoring HPV-associated cervical lesion development to cancer.

Cellular senescence is a damage response aimed to orchestrate tissue repair. We have recently reported that cellular senescence, through the paracrine release of interleukin-6 (IL6) and other soluble factors, strongly favors cellular reprogramming by Oct4, Sox2, Klf4, and c-Myc (OSKM) in nonsenescent cells. Indeed, activation of OSKM in mouse tissues triggers senescence in some cells and reprogramming in other cells, both processes occurring concomitantly and in close proximity. In this system, Ink4a/Arf-null tissues cannot undergo senescence, fail to produce IL6, and cannot reprogram efficiently; whereas p53-null tissues undergo extensive damage and senescence, produce high levels of IL6, and reprogram efficiently. Here, we have further explored the genetic determinants of in vivo reprogramming. We report that Ink4a, but not Arf, is necessary for OSKM-induced senescence and, thereby, for the paracrine stimulation of reprogramming. However, in the absence of p53, IL6 production and reprogramming become independent of Ink4a, as revealed by the analysis of Ink4a/Arf/p53 deficient mice. In the case of the cell cycle inhibitor p21, its protein levels are highly elevated upon OSKM activation in a p53-independent manner, and we show that p21-null tissues present increased levels of senescence, IL6, and reprogramming. We also report that Il6-mutant tissues are impaired in undergoing reprogramming, thus reinforcing the critical role of IL6 in reprogramming. Finally, young female mice present lower efficiency of in vivo reprogramming compared to male mice, and this gender difference disappears with aging, both observations being consistent with the known anti-inflammatory effect of estrogens. The current findings regarding the interplay between senescence and reprogramming may conceivably apply to other contexts of tissue damage., (© 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.)

Background: The preferential use of aerobic glycolysis by tumor cells lead to high accumulation of lactate in tumor microenvironment. Clinical evidence has linked elevated lactate concentration with cancer outcomes. However, the role and molecular mechanisms of lactate in cellular senescence and tumor progression remain elusive., Methods: The function of Snail in lactate-induced EMT in lung cancer cells was explored by wound healing assay and cell invasion assay. The qRT-PCR and dual luciferase reporter assay were performed to investigate how lactate regulates Snail expression. The level of TGF-β1 in culture supernatant of cells was measured by ELISA for its correlation with extracellular levels of lactate. Ras activity assay and SA-β-gal activity assay were established to determine the effect of lactate on oncogene-induced senescence in human lung epithelial cells. ChIP assays were conducted to determine the binding of snail to p16 INK4a promoter. Two TCGA data sets (TCGA-LUAD and TCGA-LUSC) were used to explore the correlations between SNAI1 and CDKN2A expression., Results: In this study, we showed the invasive and migratory potential of lung cancer cells was significantly enhanced by lactate and was directly linked to snail activity. We also demonstrated that extracellular acidification itself is a direct cause of the increased snail expression and physiologically coupled to LDHA-dependent conversion of pyruvate to lactate. Mechanistically, lactate exerts its central function in induction of snail and EMT by directly remodeling ECM and releasing activated TGF-β1. We also demonstrated that Snail help premalignant cells to escape the oncogene-induced senescence by directly targeting and inhibiting p16 INK4a expression., Conclusions: Our study extends the understanding of EMT in tumorigenesis by uncovering the role of snail in cellular senescence. This study also reveals lactate may be a potent tumor-promoting factor and provides the basis for the development of lactate-targeted therapy.

Human papilloma virus (HPV) infection is the main etiological factor for cervical intraepithelial lesions (CIN). An important characteristic of this process is the loss of genome stability. Therefore, it is imperative to use biomarkers of DNA damage caused by genomic instability to identify high risk individuals. We investigated the frequency of micronuclei (MN) in peripheral blood lymphocytes (PBL) of 20 patients, diagnosed as histologically CIN 1 and 10 healthy controls. We also examined the frequency of other nuclear anomalies including nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) in PBL of patients with CIN 1 and healthy controls, and evaluated the benefits of p16 INK4a and Ki-67 (p16 INK4a /Ki-67) immunohistochemical double staining for identifying cervical squamous cells that express HPV E6/E7 oncogenes. We analyzed the association between the frequency of MN in PBL and the amount of p16 INK4a /Ki-67 co-expression in CIN 1 patients to establish genomic instability. Among CIN 1 subjects, 15% exhibited diffuse p16 INK4a /Ki-67 co-expression and were considered high positive, 25% of the CIN 1 cases exhibited p16 INK4a /Ki-67 co-expression restricted to the lower part of the epithelium and were considered low positive and the remaining 60% of cases were negative. The frequency of MN, NPBs and NBUDs differed significantly among groups. We found a statistically significant positive correlation between p16 INK4a /Ki-67 co-expression and the frequency of MN, NPBs and NBUDs in PBL. Our findings demonstrate the efficacy of p16 INK4a /Ki-67 double immunostaining for histological samples with CIN 1. MN frequency in PBL might be useful for detecting genomic instability in cases of HPV infection and CIN.

The genomic CDKN2A/B locus, encoding p16 INK4a among others, is linked to an increased risk for cardiovascular disease and type 2 diabetes. Obesity is a risk factor for both cardiovascular disease and type 2 diabetes. p16 INK4a is a cell cycle regulator and tumour suppressor. Whether it plays a role in adipose tissue formation is unknown. p16 INK4a knock-down in 3T3/L1 preadipocytes or p16 INK4a deficiency in mouse embryonic fibroblasts enhanced adipogenesis, suggesting a role for p16 INK4a in adipose tissue formation. p16 INK4a -deficient mice developed more epicardial adipose tissue in response to the adipogenic peroxisome proliferator activated receptor gamma agonist rosiglitazone. Additionally, adipose tissue around the aorta from p16 INK4a -deficient mice displayed enhanced rosiglitazone-induced gene expression of adipogenic markers and stem cell antigen, a marker of bone marrow-derived precursor cells. Mice transplanted with p16 INK4a -deficient bone marrow had more epicardial adipose tissue compared to controls when fed a high-fat diet. In humans, p16 INK4a gene expression was enriched in epicardial adipose tissue compared to other adipose tissue depots. Moreover, epicardial adipose tissue from obese humans displayed increased expression of stem cell antigen compared to lean controls, supporting a bone marrow origin of epicardial adipose tissue. These results show that p16 INK4a modulates epicardial adipose tissue development, providing a potential mechanistic link between the genetic association of the CDKN2A/B locus and cardiovascular disease risk.

Background: There is a growing realization that COPD, or at least emphysema, involves several processes presenting in aging and cellular senescence. Endothelial progenitor cells (EPCs) contribute to neovascularization and play an important role in the development of COPD. The gene for p16 Ink4a is a major dominant senescence one. The aim of the present study was to observe changes in lung function, histomorphology of lung tissue, and expression of p16 Ink4a in lung tissue and bone marrow-derived EPCs in emphysematous mice induced by cigarette-smoke extract (CSE), and further to search for a potential candidate agent protecting against emphysema induced by CSE., Materials and Methods: An animal emphysema model was induced by intraperitoneal injection of CSE. 5-Aza-2'-deoxycytidine (5-Aza-CdR) was administered to the emphysematous mice. Lung function and histomorphology of lung tissue were measured. The p16 Ink4a protein and mRNA in EPCs and lung tissues were detected using Western blotting and quantitative reverse-transcription polymerase chain reaction, respectively., Results: CSE induced emphysema with increased p16 Ink4a expression in lung tissue and bone marrow-derived EPCs. 5-Aza-CdR partly protected against emphysema, especially in the lung-morphology profile, and partly protest against the overexpression of p16 Ink4a in EPCs and lung tissue induced by CSE., Conclusion: 5-Aza-CdR partly protected against emphysema in mice via suppressing p16 Ink4a expression in EPCs and lung tissue., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Objective: To establish a time-resolved fluoroimmunoassay (TRFIA) method to detect p16INK4a., Methods: 119 cases of exfoliative cells following Thinprep cytologic test (TCT) test were selected for TRFIA and biopsy tissues of these patients according to TCT results were collected for immunohistochemical (IHC) staining., Results: There were 40 cases with cervicitis, 16 cases of cervical intraepithelial neoplasia grade 1 (CIN1), 15 cases of CIN2, 26 cases of CIN3, and 22 cases of squamous cell carcinoma (SCC). For each group, TCT results displaying above ASC-US were 7, 6, 12, 23, and 21 cases. IHC results were positive for 2, 13, 14, 26, and 21 cases, while the TRFIA results were positive for 5, 12, 13, 25, and 21 cases, respectively. The sensitivity and specificity were not significantly different between TCT and TRFIA test due to the limited cases. Significantly more CIN1 cases were positive by TRFIA, as compared with cervicitis (75.00% vs. 12.50%, χ 2 =21.116, p<0.001). Most (93.65%) CIN2/3 and SCC cases were positive for p16INK4a (higher than CIN1, χ 2 =4.877 and p=0.027)., Conclusion: Detecting p16INK4a protein by TRFIA is suitable to discriminate cervical dysplastic/neoplastic lesions from cervicitis. A commercial kit which created in the future might be a rapid, simple, and low-cost method to obtain objective results with an instrument automatically on a large scale., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The epidermis is a self-renewing tissue. The balance between proliferation and differentiation processes is tightly regulated to ensure the maintenance of the stem cell (SC) population in the epidermis during life. Aging and cancer may be considered related endpoints of accumulating damages within epidermal self-renewing compartment. p16 INK4a is a potent inhibitor of the G1/S-phase transition of the cell cycle. p16 INK4a governs the processes of SC self-renewal in several tissues and its deregulation may result in aging or tumor development. Keratinocytes are equipped with several epigenetic enzymes and transcription factors that shape the gene expression signatures of different epidermal layers and allow dynamic and coordinated expression changes to finely balance keratinocyte self-renewal and differentiation. These factors converge their activity in the basal layer to repress p16 INK4a expression, protecting cells from senescence, and preserving epidermal homeostasis and regeneration. Several stress stimuli may activate p16 INK4a expression that orchestrates cell cycle exit and senescence response. In the present review, we discuss the role of p16 INK4a regulators in human epidermal SC self-renewal, aging and cancer., Competing Interests: The authors declare no conflict of interest.

p16 INK4A and p53 are two important tumor suppressor proteins that play essential roles during cell proliferation and aging through regulating the expression of several genes. Here, we report that p16 INK4A and p53 co-regulate a plethora of transcripts. Furthermore, both proteins colocalize in the nucleus of human primary skin fibroblasts and breast luminal cells, and form a heteromer whose level increases in response to genotoxic stress as well as aging of human fibroblasts and various mouse organs. CDK4 is also present in this heteromeric complex, which is formed only in the presence of DNA both in vitro using pure recombinant proteins and in vivo. We have also shown that p16 INK4A enhances the binding efficiency of p53 to its cognate sequence presents in the CDKN1A promoter in vitro, and both proteins are present at the promoters of CDKN1A and BAX in vivo. Importantly, the fourth ankyrin repeat of p16 INK4A and the C-terminal domain of p53 were necessary for the physical association between these two proteins. The physiologic importance of this association was revealed by the inability of cancer-associated p16 INK4A mutants to interact with p53 and to transactivate the expression of its major targets CDKN1A and BAX in the p16-defective U2OS cells expressing either wild-type or mutated p16 INK4A . Furthermore, the association between p16 INK4A and p53 was capital for their nuclear colocalization, the X-ray-dependent induction of p21 and Bax proteins as well as the induction of apoptosis in various types of cells. Together, these results show DNA-dependent physical interaction between p16 INK4A and p53., (© 2017 Wiley Periodicals, Inc.)