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Topical anticholinergics have been reported to be effective in managing hyperhidrosis (HH) given the recent approval of glycopyrronium tosylate.This review aimed to examine the effectiveness of emerging topical anticholinergic treatments for HH and their associated adverse effects in comparison to current treatment options.We conducted a search within the PubMed and Embase databases for current and emerging topical anticholinergic treatments for primary HH.The topical anticholinergics that have been recently investigated for use in HH include glycopyrrolate, oxybutynin, sofpironium bromide, and umeclidinium. The only agent currently FDA approved is glycopyrrolate.Knowledge of topical anticholinergic treatment options is important for patient care when managing HH. This review shows that while available safety data thus far are limited, emerging topical anticholinergics pose minimal known human risks.

Figure S1-3 Table S1-2

Purpose:Squamous cell carcinoma (SCC) of the skin is the leading cause of death in patients with the severe generalized form of the genetic disease recessive dystrophic epidermolysis bullosa (RDEB). Although emerging data are identifying why patients suffer this fatal complication, therapies for treatment of RDEB SCC are in urgent need.Experimental Design: We previously identified polo-like kinase 1 (PLK1) as a therapeutic target in skin SCC, including RDEB SCC. Here, we undertake a screen of 6 compounds originally designated as PLK1 inhibitors, and detail the efficacy of the lead compound, the multipathway allosteric inhibitor ON-01910, for targeting RDEB SCC in vitro and in vivo.Results:ON-01910 (or rigosertib) exhibited significant specificity for RDEB SCC: in culture rigosertib induced apoptosis in 10 of 10 RDEB SCC keratinocyte populations while only slowing the growth of normal primary skin cells at doses 2 orders of magnitude higher. Furthermore, rigosertib significantly inhibited the growth of two RDEB SCC in murine xenograft studies with no apparent toxicity. Mechanistically, rigosertib has been shown to inhibit multiple signaling pathways. Comparison of PLK1 siRNA with MEK inhibition, AKT inhibition, and the microtubule-disrupting agent vinblastine in RDEB SCC shows that only PLK1 reduction exhibits a similar sensitivity profile to rigosertib.Conclusions:These data support a "first in RDEB" phase II clinical trial of rigosertib to assess tumor targeting in patients with late stage, metastatic, and/or unresectable SCC.

As the cosmeceutical market for nail products is growing, there is an emerging need for dermatologists to provide patients with evidence-based information regarding over-the-counter products and supplements for nail growth. By law, there is no required efficacy and safety assessment by the Food and Drug Administration prior to these products being made available to consumers. This carries financial and health consequences for patients seeking affordable and effective over-the-counter products to improve their nail conditions. In this comprehensive review, we discuss available oral nail growth products, their mechanisms of action, and side effects.

Dermatology involves various occupational hazards that threaten the safety of practicing dermatologists and may often go unrecognized and ignored. These dangers may appear minor but with the daily volume of patients examined by dermatologists do pose significant health risks. A review of the occupational hazards and exposures frequently encountered in the field of dermatology would be beneficial for both dermatologists and patients. In this review, we conducted a comprehensive search of published studies from inception to May 30, 2021 using the terms "dermatology," "occupational exposure," and "biohazard" in PubMed-MEDLINE, Google Scholar, Embase, and Cochrane Central to summarize occupational hazards in dermatology. (

Joshua Brady,1 Reem Kashlan,1 Julie Ruterbusch,2 Mehdi Farshchian,3 Meena Moossavi3 1Wayne State University School of Medicine, Detroit, MI, USA; 2Department of Oncology, Wayne State University, Detroit, MI, USA; 3Department of Dermatology, Wayne State University, Detroit, MI, USACorrespondence: Mehdi FarshchianDepartment of Dermatology, Wayne State University, 18100 Oakwood Blvd., Suite 300, Dearborn, MI, 48124 Email mfarshch@med.wayne.eduPurpose: As the most common cause of skin cancer death, incidence and mortality of melanoma vary widely between ethnic and racial groups.Methods: Surveillance, Epidemiology, and End Results (SEER) data were used to examine the incidence and survival in patients with melanoma concerning race and ethnicity in Wayne County, Michigan between 2000 and 2016.Results: Analysis of data revealed significantly higher melanoma-specific death in non-Hispanic black patients compared to their non-Hispanic white counterparts (p < 0.001). However, no increased risk of death due to melanoma was observed following adjustment of data for the stage, age, and sex (H.R. = 1.00, 95% CI 0.64– 1.56).Conclusion: Non-Hispanic black patients have the highest percentage of late-stage melanoma. Increased incidence of melanoma mortality in non-Hispanic black patients is likely a consequence of late-stage diagnosis.Keywords: melanoma, racial disparities, epidemiology, clinical research, skin of color

Lack of type VII collagen (C7) disrupts cellular proteostasis yet the mechanism remains undescribed. By studying the relationship between C7 and the extracellular matrix (ECM)-associated proteins thrombospondin-1 (TSP1), type XII collagen (C12) and tissue transglutaminase (TGM2) in primary human dermal fibroblasts from multiple donors with or without the genetic disease recessive dystrophic epidermolysis bullosa (RDEB) (n=31), we demonstrate that secretion of each of these proteins is increased in the presence of C7. In dermal fibroblasts isolated from patients with RDEB, where C7 is absent or defective, association with the COPII outer coat protein SEC31 and ultimately secretion of each of these ECM-associated proteins is reduced and intracellular levels are increased. In RDEB fibroblasts, overall collagen secretion (as determined by the levels of hydroxyproline in the media) is unchanged while traffic from the ER to Golgi of TSP1, C12 and TGM2 occurs in a type I collagen (C1) dependent manner. In normal fibroblasts association of TSP1, C12 and TGM2 with the ER exit site transmembrane protein Transport ANd Golgi Organization-1 (TANGO1) as determined by proximity ligation assays, requires C7. In the absence of wild-type C7, or when ECM-associated proteins are overexpressed, C1 proximity and intracellular levels increase resulting in elevated cellular stress responses and elevated TGFβ signaling. Collectively, these data demonstrate a role for C7 in loading COPII vesicle cargo and provides a mechanism for disrupted proteostasis, elevated cellular stress and increased TGFβ signaling in patients with RDEB. Furthermore, our data point to a threshold of cargo loading that can be exceeded with increased protein levels leading to pathological outcomes in otherwise normal cells.

Kathren H Shango,1 Fouad A Abdole,1 Sarah M Gonzalez,1 Mehdi Farshchian,2 Meena Moossavi2 1Wayne State University School of Medicine, Detroit, MI, USA; 2Department of Dermatology, Wayne State University, Detroit, MI, USACorrespondence: Mehdi Farshchian, Department of Dermatology, Wayne State University, 18100 Oakwood Blvd., Suite 300, Dearborn, MI, 48124, USA, Email mfarshch@med.wayne.eduPurpose: To evaluate medical student confidence in diagnosing dermatologic diseases in skin of color.Methods: A voluntary supplemental module was implemented as part of the second-year dermatology curriculum at Wayne State University School of Medicine (WSU SOM) in Detroit, Michigan. The goal of the module was to ascertain whether it may increase confidence in students with their approach to diagnosing diseases in darker skin tones.Results: Seventy-seven of 295 students (26%) completed a “Skin of Color” optional module consisting of thirteen cases of common skin pathologies in African American patients. A pre- and post-survey performed to assess students’ confidence using a five-point Likert scale. After completing the module, medical students demonstrated a statistically significant increase in confidence in diagnosing skin pathologies in skin of color.Conclusion: Dermatology pre-clinical course work should include supplementary materials to increase student confidence in diagnosing skin diseases in darker skin tones.Keywords: medical education, health disparities, epidemiology, skin of color

Plantar warts are among the most common skin conditions and are classically resistant to treatment. To perform an evidence-based evaluation of the efficacy and safety of available treatment options for plantar warts, we conducted a systematic review of PubMed and Cochrane databases to identify large interventional and observational studies involving more than 100 patients who were treated for plantar warts from inception to October 2020. We identified only nine contributions meeting our inclusion criteria (N ≥ 100), representing 1,657 adult and pediatric patients with plantar warts. Treatments included in this review were topical keratolytic agents, cryotherapy, laser therapies, and intralesional and systemic treatments. Our evidence-based review of the larger studies suggests keratolytic agents and destructive treatments, in particular salicylic acid and cryotherapy, remain the primary treatments for plantar warts. Treatment with pulsed dye laser had the lowest rate of recurrence. Newer treatments and intralesional treatments were not represented owing to lack of large studies involving these modalities.

Background Palmar and plantar hyperhidrosis (HH) is a common condition characterized by excessive sweating of the palms and soles. Botulinum neurotoxin (BTX) is a very effective and safe treatment. However, the associated intense injection pain is a major limiting factor deterring patients from selecting this treatment. Objective The aim of this study was to review the numerous techniques used to minimize pain accompanying injections for palmoplantar HH. Additionally, the advantages and limitations of each modality will be discussed. Materials and methods The authors performed a comprehensive literature search in PubMed/MEDLINE, Embase, Cochrane Central, and Google Scholar on randomized controlled trials, cohort studies, and case series on techniques to relieve pain of BTX injections for treatment of palmar and plantar HH. Results Current available techniques in reducing botulinum injection with merits and drawbacks are nerve blocks, Bier blocks, cryoanalgesia, needle-free anesthesia, topical anesthetics, and vibration anesthesia. Conclusion Topical anesthesia, ice, and vibration are the safest and most convenient noninvasive available methods to relieve pain associated with botulinum injection. Nerve blocks, Bier block, and needle-free anesthesia provide better anesthesia but are limited by the need for training and equipment.

We present a case of a one-month-old female patient with severe hypertriglyceridaemia as a side effect of treating an ulcerating infantile hemangioma with systemic propranolol. The remarkedly rapid increase in triglyceride returned to normal 96 hours after the discontinuation of the medication, and further follow-up revealed normalisation of the lipid profile. Further research is necessary to unveil the association of systemic propranolol with hypertriglyceridaemia.

Summary Background The incidence of epidermal keratinocyte‐derived cutaneous squamous cell carcinoma (cSCC) is increasing worldwide. Objectives To study the role of the complement classical pathway components C1q, C1r and C1s in the progression of cSCC. Methods The mRNA levels of C1Q subunits and C1R and C1S in cSCC cell lines, normal human epidermal keratinocytes, cSCC tumours in vivo and normal skin were analysed with quantitative real‐time polymerase chain reaction. The production of C1r and C1s was determined with Western blotting. The expression of C1r and C1s in tissue samples in vivo was analysed with immunohistochemistry and further investigated in human cSCC xenografts by knocking down C1r and C1s. Results Significantly elevated C1R and C1S mRNA levels and production of C1r and C1s were detected in cSCC cells, compared with normal human epidermal keratinocytes. The mRNA levels of C1R and C1S were markedly elevated in cSCC tumours in vivo compared with normal skin. Abundant expression of C1r and C1s by tumour cells was detected in invasive sporadic cSCCs and recessive dystrophic epidermolysis bullosa‐associated cSCCs, whereas the expression of C1r and C1s was lower in cSCC in situ, actinic keratosis and normal skin. Knockdown of C1r and C1s expression in cSCC cells inhibited activation of extracellular signal‐related kinase 1/2 and Akt, promoted apoptosis of cSCC cells and significantly suppressed growth and vascularization of human cSCC xenograft tumours in vivo. Conclusions These results provide evidence for the role of tumour‐cell‐derived C1r and C1s in the progression of cSCC and identify them as biomarkers and putative therapeutic targets in cSCC. What's already known about this topic? The incidences of actinic keratosis, cutaneous squamous cell carcinoma (cSCC) in situ and invasive cSCC are increasing globally.Few specific biomarkers for progression of cSCC have been identified, and no biological markers are in clinical use to predict the aggressiveness of actinic keratosis, cSCC in situ and invasive cSCC. What does this study add? Our results provide novel evidence for the role of complement classical pathway components C1r and C1s in the progression of cSCC. What is the translational message? Our results identify complement classical pathway components C1r and C1s as biomarkers and putative therapeutic targets in cSCC., Linked Comment: https://doi.org/10.1111/bjd.18419. https://doi.org/10.1111/bjd.18821 available online

Summary DACH1 abundance is reduced in human malignancies, including breast cancer. Herein DACH1 was detected among multipotent fetal mammary stem cells in the embryo, among mixed lineage precursors, and in adult basal cells and (ERα+) luminal progenitors. Dach1 gene deletion at 6 weeks in transgenic mice reduced ductal branching, reduced the proportion of mammary basal cells (Lin− CD24med CD29high) and reduced abundance of basal cytokeratin 5, whereas DACH1 overexpression induced ductal branching, increased Gata3 and Notch1, and expanded mammosphere formation in LA-7 breast cells. Mammary gland-transforming growth factor β (TGF-β) activity, known to reduce ductal branching and to reduce the basal cell population, increased upon Dach1 deletion, associated with increased SMAD phosphorylation. Association of the scaffold protein Smad anchor for receptor activation with Smad2/3, which facilitates TGF-β activation, was reduced by endogenous DACH1. DACH1 increases basal cells, enhances ductal formation and restrains TGF-β activity in vivo., Highlights • Dach1 is expressed in mammary gland fetal stem cells and adult luminal cells • Dach1 expands mammary gland basal/myoepithelial cells • Dach1 induces post-natal mammary gland ductal formation • Dach1 retrains TGF-β activity in the mammary gland in vivo, DACH1 abundance, is reduced in human malignancies, including breast cancer. In this article, Dr. Pestell and his colleagues showed that DACH1 is expressed in multipotent mammary gland fetal stem cells and both the adult basal and ERα+ luminal cells, promotes mammary gland stem cell and basal/myoepithelial cell expansion, promotes mammary gland ductal branching, and restrains TGF-β action in the pubertal mammary gland.

Hyperhidrosis (HH) is defined as perspiration beyond the level required to maintain temperature regulation. HH affects nearly 4.8% of the population in the United States. It can have a great impact on patientrsquo;s quality of life by disturbing daily activity, performance, confidence, social interactions, and mental health. In the majority of patients with HH (93%), the etiology of excess sweating is idiopathic, which classifies it as primary focal HH. Mild HH may be controlled with topical antiperspirants and lifestyle modifications. Based on the location of involvement, iontophoresis and botulinum toxin may be considered if the patient does not respond to topical therapies. Despite minimizing sweating, chronic use of systemic anticholinergics, in particular oxybutynin, may result in detrimental adverse effects such as dementia. Local surgery, radiofrequency, microwave, and lasers are other potential modalities for HH. Sympathectomy can be a last resort for the treatment of focal HH of the palmar, plantar, axillary, and craniofacial areas after failure of less invasive therapeutic options. In this review, we conducted a comprehensive search in the PubMed electronic database to summarize an algorithmic approach for the treatment of HH. This can help broaden options for managing this difficult disease. J Drugs Dermatol. 20(5): doi:10.36849/JDD.5774.

The corona virus disease (COVID-19) is a novel disease that can lead to fatal outcomes in infected individuals. Messenger RNA (mRNA) vaccines are two of the three Food and Drug Administration (FDA) approved vaccines in the United States (US) to date. Disclosed side effects by the Centers for Disease Control and Prevention (CDC) included tiredness, headache, muscle pain, chills, fever, and nausea. 1,2 A variety of other adverse effects are continuously being reported in individual patients. We describe a case of localized cutaneous reaction to a mRNA vaccine.

Long noncoding RNAs (lncRNAs) have emerged as putative biomarkers and therapeutic targets in cancer. The role of lncRNA LINC00346 in cutaneous squamous carcinoma (cSCC) was examined. The expression of LINC00346 was up-regulated in cSCC cells compared with normal human epidermal keratinocytes. Elevated expression of LINC00346 was noted in tumor cells in cSCC tissue sections in vivo, as compared with cSCC in situ, and actinic keratosis by RNA in situ hybridization; and the expression in seborrheic keratosis and normal skin was very low. Immunohistochemical analysis of cSCC tissue sections and functional assays of cSCC cells in culture showed that LINC00346 expression is down-regulated by p53. Knockdown of LINC00346 inhibited invasion of cSCC cells in culture and suppressed growth of human cSCC xenografts in vivo. Knockdown of LINC00346 inhibited expression of activated STAT3 and resulted in down-regulation of the expression of matrix metalloproteinase (MMP)-1, MMP-3, MMP-10, and MMP-13. Based on these observations LINC00346 was named p53 regulated carcinoma-associated STAT3-activating long intergenic non-protein coding transcript (PRECSIT). These results identify PRECSIT as a new p53-regulated lncRNA, which promotes progression of cSCC via STAT3 signaling.

Purpose: Squamous cell carcinoma (SCC) of the skin is the leading cause of death in patients with the severe generalized form of the genetic disease recessive dystrophic epidermolysis bullosa (RDEB). Although emerging data are identifying why patients suffer this fatal complication, therapies for treatment of RDEB SCC are in urgent need. Experimental Design: We previously identified polo-like kinase 1 (PLK1) as a therapeutic target in skin SCC, including RDEB SCC. Here, we undertake a screen of 6 compounds originally designated as PLK1 inhibitors, and detail the efficacy of the lead compound, the multipathway allosteric inhibitor ON-01910, for targeting RDEB SCC in vitro and in vivo. Results: ON-01910 (or rigosertib) exhibited significant specificity for RDEB SCC: in culture rigosertib induced apoptosis in 10 of 10 RDEB SCC keratinocyte populations while only slowing the growth of normal primary skin cells at doses 2 orders of magnitude higher. Furthermore, rigosertib significantly inhibited the growth of two RDEB SCC in murine xenograft studies with no apparent toxicity. Mechanistically, rigosertib has been shown to inhibit multiple signaling pathways. Comparison of PLK1 siRNA with MEK inhibition, AKT inhibition, and the microtubule-disrupting agent vinblastine in RDEB SCC shows that only PLK1 reduction exhibits a similar sensitivity profile to rigosertib. Conclusions: These data support a "first in RDEB" phase II clinical trial of rigosertib to assess tumor targeting in patients with late stage, metastatic, and/or unresectable SCC.

Closing defects under tension in areas such as the scalp and back may be challenging during dermatologic surgery. Different techniques have been advocated to ease the placement of the first deep suture under tension, including the slip-knot stitch, pully stitch, horizontal mattress suture, pulley set-back dermal suture, and tandem pulley stitch.

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare inherited skin and mucous membrane fragility disorder complicated by early-onset, highly malignant cutaneous squamous cell carcinomas (SCCs). The molecular etiology of RDEB SCC, which arises at sites of sustained tissue damage, is unknown. We performed detailed molecular analysis using whole-exome, whole-genome, and RNA sequencing of 27 RDEB SCC tumors, including multiple tumors from the same patient and multiple regions from five individual tumors. We report that driver mutations were shared with spontaneous, ultraviolet (UV) light-induced cutaneous SCC (UV SCC) and head and neck SCC (HNSCC) and did not explain the early presentation or aggressive nature of RDEB SCC. Instead, endogenousmutation processes associated with apolipoprotein B mRNA-editing enzymecatalytic polypeptide-like (APOBEC) deaminases dominated RDEB SCC. APOBEC mutation signatures were enhanced throughout RDEB SCC tumor evolution, relative to spontaneous UV SCC and HNSCCmutation profiles. Sixty-seven percent of RDEB SCC driver mutations was found to emerge as a result of APOBEC and other endogenous mutational processes previously associated with age, potentially explaining a > 1000-fold increased incidence and the early onset of these SCCs. Human papillomavirus-negative basal and mesenchymal subtypes of HNSCC harbored enhanced APOBEC mutational signatures and transcriptomes similar to those of RDEB SCC, suggesting thatAPOBECdeaminases drive other subtypes of SCC. Collectively, these data establish specific mutagenic mechanisms associated with chronic tissue damage. Our findings reveal a cause for cancers arising at sites of persistent inflammation and identify potential therapeutic avenues to treat RDEB SCC.

Purpose The two main etiological factors for vulvar squamous cell carcinoma (vSCC) are the vulvar dermatosis lichen sclerosus (LS) and high-risk human papillomavirus (hrHPV). Serpin A1 (α1-antitrypsin) is a serine protease inhibitor, which plays a role in the tumorigenesis of various cancer types. The aim of the study was to evaluate the expressions of Serpin A1 in LS, premalignant vulvar lesions, and vSCC using immunohistochemistry (IHC) and serum analysis, and to compare Serpin A1 stainings to the tumor markers p53 and p16. Methods In total, 120 samples from 74 patients were studied with IHC for Serpin A1, p53 and p16: 18 normal vulvar skin, 53 LS, 9 premalignant vulvar lesions (dVIN/HSIL) and 40 vSCC samples. Serum concentrations of Serpin A1 were analyzed from 30 LS, 44 vSCC and 10 control patients. Expressions were compared to clinical data. Results Tumor cell-specific Serpin A1 overexpression was detected in 88% of vSCC samples, independent of the etiology. The intensity of Serpin A1 expression was significantly higher in vSCC than in healthy vulvar skin, LS, or premalignant vulvar lesions. Serpin A1 showed an association with p53 positivity. No difference in overall survival was found between Serpin A1-, p53-, or p16-positive vSCC patients. Serum concentrations of Serpin A1 were equal in the LS, vSCC, and control groups. Conclusion Tumor cell-specific Serpin A1 overexpression is a potential biomarker in vSCC.

Keratinocyte-derived skin cancer, cutaneous squamous cell carcinoma (cSCC), is the most common metastatic skin cancer. We have examined the role of Eph/ephrin signaling in the progression of cSCC. Analysis of the expression of EPH and EFN families in cSCC cells and normal epidermal keratinocytes revealed overexpression of EPHB2 mRNA in cSCC cells and cSCC tumors in vivo . Tumor cell–specific overexpression of EphB2 was detected in human cSCCs and in chemically induced mouse cSCCs with immunohistochemistry, whereas the expression of EphB2 was low in premalignant lesions and normal skin. Knockdown of EphB2 expression in cSCC cells suppressed growth and vascularization of cSCC xenografts in vivo and inhibited proliferation, migration, and invasion of cSCC cells in culture. EphB2 knockdown downregulated expression of genes associated with biofunctions cell viability , migration of tumor cells , and invasion of tumor cells . Among the genes most downregulated by EphB2 knockdown were MMP1 and MMP13 . Moreover, activation of EphB2 signaling by ephrin-B2-Fc enhanced production of invasion proteinases matrix metalloproteinase-13 (MMP13) and MMP1, and invasion of cSCC cells. These findings provide mechanistic evidence for the role of EphB2 in the early progression of cSCC to the invasive stage and identify EphB2 as a putative therapeutic target in this invasive skin cancer.

Mahmood Farshchian,1 Akram Ansar,1 Abbas Zamanian,2 Ghasem Rahmatpour-Rokni,1 Arash Kimyai-Asadi,3 Mehdi Farshchian1,4 1Psoriasis Research Center, Department of Dermatology, Farshchian Hospital, Hamadan University of Medical Sciences, Hamedan, Iran; 2Department of Dermatology, Iran University of Medical Sciences, Tehran, Iran; 3Derm Surgery Associates, Houston, TX, USA; 4Department of Dermatology, University of Turku and Turku University Hospital, Turku, Finland Background: The aim of this study was to analyze the clinical characteristics of patients with adverse cutaneous drug reactions, which occur when a medicinal product results in cutaneous morbidity. Methods: The study included 308 patients who were diagnosed as having an adverse cutaneous drug reaction during the study period (2007–2009). In 84 cases, histopathologic examination of skin biopsies were also performed. Results: Patients with drug reactions were found to be more commonly female (63%) than male (37%). Beta-lactam antibiotics were found to be the most frequent cause of adverse cutaneous drug reactions (42.7%), followed by non-steroidal anti-inflammatory drugs (16.5%). Acute urticaria was the most common clinical presentation (59.2%) followed by fixed drug eruptions (18.5%), and maculopapular eruptions (14.9%). Conclusion: Adverse cutaneous drug reactions in our study population were mainly induced by beta-lactam antibiotics and non-steroidal anti-inflammatory drugs. The most common forms of cutaneous adverse drug reactions were found to be acute urticaria, fixed drug eruptions, and maculopapular rashes. Keywords: adverse drug reaction, acute urticaria, exanthematous eruption

The incidence of cutaneous squamous cell carcinoma (cSCC) is rising worldwide. We have examined the role of complement components in the progression of cSCC. Analysis of cSCC cell lines (n=8) and normal human epidermal keratinocytes (n=11) with whole transcriptome profiling (SOLiD), quantitative real-time reverse transcriptase–PCR, and western blotting revealed marked overexpression of complement factor I (CFI) in cSCC cells. Immunohistochemical analysis for CFI in vivo showed stronger tumor cell–specific labeling intensity in invasive sporadic cSCCs (n=83) and recessive dystrophic epidermolysis bullosa–associated cSCCs (n=7) than in cSCC in situ (n=65), premalignant epidermal lesions (actinic keratoses, n=64), benign epidermal papillomas (seborrheic keratoses, n=39), and normal skin (n=9). The expression of CFI was higher in the aggressive Ha-ras-transformed cell line (RT3) than in less tumorigenic HaCaT cell lines (HaCaT, A5, and II-4). The expression of CFI by cSCC cells was upregulated by IFN-γ and IL-1β. Knockdown of CFI expression inhibited proliferation and migration of cSCC cells and resulted in inhibition of basal extracellular signal–regulated kinase (ERK) 1/2 activation. Knockdown of CFI expression potently inhibited growth of human cSCC xenograft tumors in vivo. These results provide evidence for the role of CFI in the progression of cSCC and identify it as a potential therapeutic target in this nonmelanoma skin cancer.

The incidence of cutaneous squamous cell carcinoma (cSCC) is rapidly increasing, and the prognosis of patients with metastatic disease is poor. There is an emerging need to identify molecular markers for predicting aggressive behaviour of cSCC. Here, we have examined the role of tight junction (TJ) components in the progression of cSCC. The expression pattern of mRNAs for TJ components was determined with RNA sequencing and oligonucleotide array-based expression analysis from cSCC cell lines (n=8) and normal human epidermal keratinocytes (NHEK, n=5). The expression of CLDN11 was specifically elevated in primary cSCC cell lines (n=5), but low or absent in metastatic cSCC cell lines (n=3) and NHEKs. Claudin-11 was detected in cell-cell contacts of primary cSCC cells in culture by indirect immunofluorescence analysis. Analysis of a large panel of tissue samples from sporadic UV-induced cSCC (n=65), cSCC in situ (n=56), actinic keratoses (n=31), seborrhoeic keratoses (n=7) and normal skin (n=16) by immunohistochemistry showed specific staining for claudin-11 in intercellular junctions of keratinizing tumor cells in well and moderately differentiated cSCCs, whereas no staining for claudin-11 was detected in poorly differentiated tumors. The expression of claudin-11 in cSCC cells was dependent on the activity of p38δ MAPK and knock-down of claudin-11 enhanced cSCC cell invasion. These findings provide evidence for the role of claudin-11 in regulation of cSCC invasion and suggest loss of claudin-11 expression in tumor cells as a biomarker for advanced stage of cSCC.

Cutaneous squamous cell carcinoma (cSCC) is one of the most common metastatic skin cancers with increasing incidence. We examined the roles of complement component C3 and complement factor B (CFB) in the growth of cSCC. Analysis of cSCC cell lines (n = 8) and normal human epidermal keratinocytes (n = 11) with real-time quantitative PCR and Western blotting revealed up-regulation of C3 and CFB expression in cSCC cells. Immunohistochemical staining revealed stronger tumor cell-specific labeling for C3 and CFB in invasive cSCCs (n = 71) and recessive dystrophic epidermolysis bullosa-associated cSCCs (n = 11) than in cSCC in situ (n = 69), actinic keratoses (n = 63), and normal skin (n = 5). Significant up-regulation of C3 and CFB mRNA expression was noted in chemically induced mouse cSCCs, compared to benign papillomas. Knockdown of C3 and CFB expression inhibited migration and proliferation of cSCC cells and resulted in potent inhibition of extracellular signal-regulated kinase 1/2 activation. Knockdown of C3 and CFB markedly inhibited growth of human cSCC xenograft tumors in vivo. These results provide evidence for the roles of C3 and CFB in the development of cSCC and identify them as biomarkers and potential therapeutic targets in this metastatic skin cancer.

Epidermal keratinocyte-derived cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer, and its incidence is increasing worldwide. Solar UV radiation is an important risk factor for cSCC and leads to genetic and epigenetic changes both in epidermal keratinocytes and dermal cells. Tumor cells in cutaneous cSCCs typically harbor several driver gene mutations, but epidermal keratinocytes in sun-exposed normal skin also contain mutations in these same genes. Therefore, alterations in the microenvironment of premalignant lesions are evidently required for their progression to invasive and metastatic cSCC. For example, alterations in the composition of basement membrane and dermal extracellular matrix are early events in cSCC progression. The presence of microbial structures and the influx of inflammatory cells promote the secretion of proteases, which in turn regulate the availability of growth factors, cytokines, and chemokines and thus influence the growth and invasion of cSCC. Together, these observations emphasize the role of the tumor microenvironment in the progression of cSCC and identify it as a novel therapeutic target in cSCC and other malignant tumors. Graphical abstract Tumor-stroma interactions in the progression of cutaneous squamous cell carcinoma (cSCC). Epidermal layer is separated by a well-organized basement membrane (BM) from the dermal layer. UV radiation, other environmental insults, and aging target both epidermal keratinocytes and dermal fibroblasts and lead to genetic and epigenetic changes in these cells. In addition, epidermal keratinocytes in normal sun-exposed skin harbor several mutations in the cSCC driver genes. During transition to premalignant actinic keratosis (AK), the differentiation of keratinocytes is disturbed resulting in a neoplastic epithelium with hyperplastic cells. Expression of proteinases, such as matrix metalloproteinases (MMP) by neoplastic cells and activated stromal fibroblasts and macrophages is induced in AK, and collagen XV and XVIII are lost from the dermal BM. Furthermore, inflammatory cells accumulate at the site of the hyperplastic epithelium. During a later stage of cSCC progression, the number of inflammatory cells increases, and the expression of complement components and inhibitors by tumor cells is induced (CFI complement factor I, CFH complement factor H, FHL-1 Factor H-like protein 1). In addition to MMPs, activated fibroblasts also produce growth factors and promote inflammation, growth, and invasion of tumor cells.

Keratinocyte-derived cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer, and its incidence is increasing globally. Long noncoding RNAs (lncRNA) are involved in various biological processes, and their role in cancer progression is emerging. Whole transcriptome analysis of cSCC cells (n = 8) and normal human epidermal keratinocytes (n = 4) revealed overexpression of long intergenic ncRNA (LINC00162) in cSCC cells. The expression of LINC00162 in cSCC cells was upregulated by inhibition of the p38α and p38δ mitogen-activated protein kinases. Analysis of tissue sections by RNA in situ hybridization showed that LINC00162 is specifically expressed by tumor cells in cSCCs but not by keratinocytes in normal skin in vivo. Knockdown of LINC00162 inhibited proliferation and migration of cSCC cells, and suppressed the growth of human cSCC xenografts in vivo. Furthermore, knockdown of LINC00162 inhibited extracellular signal-regulated kinase 1/2 activity and upregulated expression of dual specificity phosphatase 6 (DUSP6) in cSCC cells. Based on these observations, LINC00162 was named p38 inhibited cutaneous squamous cell carcinoma associated lincRNA (PICSAR). Our results provide mechanistic evidence for the role of PICSAR in promoting cSCC progression via activation of extracellular signal-regulated kinase 1/2 signaling pathway by downregulating DUSP6 expression. These results also identify PICSAR as a biomarker and putative therapeutic target in cSCC.

The incidence of cutaneous squamous cell carcinoma (cSCC) is increasing worldwide. We have analyzed the role of complement components C1r and C1s in the progression of cSCC. Analysis of cSCC cell lines (n=8) and normal human epidermal keratinocytes (NHEK)(n=11) with oligonucleotide arrays, RNA-seq and quantitative RT-PCR revealed significantly elevated C1r and C1s mRNA levels in cSCC cell lines. Western blot analysis showed increased production of C1r and C1s in cSCC cells compared to NHEKs. The mRNA levels for C1r and C1s were markedly elevated in cSCC tumors (n=6) compared to normal skin (n=11) in vivo. Immunohistochemical analysis for C1r and C1s revealed strong tumor cell specific expression of C1r and C1s in invasive sporadic cSCCs (n=164) and recessive dystrophic epidermolysis bullosa-associated cSCCs (n=16), whereas the expression of both was clearly lower in cSCC in situ (n=63), in premalignant epidermal lesions (actinic keratoses, n=61), and in normal skin (n=9). Knockdown of C1r and C1s expression with two specific siRNAs inhibited proliferation of cSCC cells and growth of human cSCC xenograft tumors in vivo. These results provide evidence for the role of tumor cell-derived C1r and C1s in the progression of cSCC independently of C1q and identify these serine proteinases as putative therapeutic targets in unresectable and metastatic cSCC. Citation Format: Pilvi Riihilä, Liisa Nissinen, Mehdi Farshchian, Markku Kallajoki, Atte Kivisaari, Seppo Meri, Reidar Grénman, Sirkku Peltonen, Juha Peltonen, Veli-Matti Kähäri. Tumor cell-derived complement components C1r and C1s promote growth of cutaneous squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5214.