Search

Treatment of locally advanced rectal cancer includes chemotherapy, radiation, and surgery but patient responses to neoadjuvant treatment are variable. We have shown that rectal tumors are comprised of multiple genetically distinct sub-clones. Unique sub-clones within tumors may harbor mutations which contribute to inter-patient variation in response to neoadjuvant chemoradiotherapy (nCRT). Analysis of the influence of nCRT on the extent and nature of intra-tumoral genetic heterogeneity in rectal cancer may provide insights into mechanisms of resistance. Locally advanced rectal cancer patients underwent pre-treatment biopsies. At the time of surgery, tissue from the treated tumor was obtained and analyzed. Pre- and post-treatment specimens were subjected to whole exome and confirmatory deep sequencing for somatic mutations. Copy number variation was assessed using OncoScan SNP arrays. Genomic data were analyzed using PyClone to identify sub-clonal tumor population following nCRT. Alterations that persisted or were enriched in the post-treatment tumor specimen following nCRT were defined for each patient. Thirty-two samples were obtained from ten patients. PyClone identified 2 to 10 genetic sub-clones per tumor. Substantial changes in the proportions of individual sub-clones in pre- versus post-treatment tumor material were found in all patients. Resistant sub-clones recurrently contained mutations in TP53, APC, ABCA13, MUC16, and THSD4. Recurrent copy number variation was observed across multiple chromosome regions after nCRT. Pathway analysis including variant alleles and copy number changes associated with resistant sub-clones revealed significantly altered pathways, especially those linked to the APC and TP53 genes, which were the two most frequently mutated genes. Intra-tumoral heterogeneity is evident in pre-treatment rectal cancer. Following treatment, sub-clonal populations are selectively modified and enrichment of a subset of pre-treatment sub-clones is seen. Further studies are needed to define recurrent alterations at diagnosis that may contribute to resistance to nCRT., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Aim: To evaluate the value of pretreatment blood biomarkers in predicting pathologic responses to neoadjuvant chemoradiotherapy (neo-CRT) in patients with locally advanced rectal cancer.  Materials & methods: We conducted logistic regression analysis and receiver operating characteristic to assess the predictive value of blood biomarkers. The outcome was defined by the pathologic complete response and good response. Results: Carcinoembryonic antigen (CEA) (p < 0.001), neutrophil-to-lymphocyte ratio (p = 0.024), platelet-to-lymphocyte ratio (p = 0.006) and lymphocyte-to-monocyte ratio (LMR) (p < 0.001) were significant predictors of pathologic complete response, with area under the curve of 0.785, 0.794, 0.740 and 0.913, respectively; CEA (p = 0.007) and LMR (p < 0.001) correlated significantly with good response, with area under the curve of 0.743 and 0.771, respectively. Conclusion: Lower LMR and higher CEA, neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio before treatment could predict poorer pathologic response to neo-CRT in patients with locally advanced rectal cancer.

Objective: To provide biomarkers related to the radiation response of patients to avoid unnecessary side effects on those who were not sensitive to radiotherapy., Patients and Methods: In the present study, we compared the different four proteins (PDIA3, Vimentin, Galectin3, Dhe3) patterns in rectal tumor tissue before and after radiation therapy by using 2-D PAGE, mass spectrometry, and bioinformatics analysis., Results: The protein level of Galectin3 and PDIA3 were downregulated in rectal cancer patients before and after radiotherapy (1.42 folds); while Dhe3 protein and Vimentin were upregulated (1-2 folds), and we also revealed Vimentin as its role in the negative regulation of the well-known transcription factor ATF4., Conclusions: Our study showed that four candidate proteins, including PIDA3, Galectin3, Dhe3, and Vimentin, might be the potential biomarkers in the identification of radiation response in rectal cancer.

Purpose: Molecular properties associated with complete response or acquired resistance to concurrent chemotherapy and radiotherapy (CRT) are incompletely characterized. Experimental Design: We performed integrated whole-exome/transcriptome sequencing and immune infiltrate analysis on rectal adenocarcinoma tumors prior to neoadjuvant CRT (pre-CRT) and at time of resection (post-CRT) in 17 patients [8 complete/partial responders, 9 nonresponders (NR)]., Results: CRT was not associated with increased tumor mutational burden or neoantigen load and did not alter the distribution of established somatic tumor mutations in rectal cancer. Concurrent KRAS / TP53 mutations (KP) associated with NR tumors and were enriched for an epithelial-mesenchymal transition transcriptional program. Furthermore, NR was associated with reduced CD4/CD8 T-cell infiltrates and a post-CRT M2 macrophage phenotype. Absence of any local tumor recurrences, KP/NR status predicted worse progression-free survival, suggesting that local immune escape during or after CRT with specific genomic features contributes to distant progression., Conclusions: Overall, while CRT did not impact genomic profiles, CRT impacted the tumor immune microenvironment, particularly in resistant cases., (©2019 American Association for Cancer Research.)

Rectal squamous cell carcinoma (SCC) is a rare tumor with unresolved etiology. Human immunodeficiency virus-infected individuals and solid organ transplant recipients experience >30-fold and approximately 3-fold elevated rates of rectal SCC, respectively, suggesting immunosuppression plays a role. 1 Human immunodeficiency virus-infected homosexual men have >60-fold higher rates of rectal SCC, similar to anal SCC. These patterns, which differ from the more common rectal adenocarcinoma (AdCA), raise the possibility of shared etiology between rectal and anal SCC, with human papillomavirus type 16 (HPV16) being a likely candidate. 2 ., (Copyright © 2019 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background and Study Aims: Evidence shows that vitamin D and cyclooxygenase type 2 (COX-2) might play role in aetiology/progression of cancer. It is suggested that antitumour effect of vitamin D depends on vitamin D-receptor (VDR) expression. Aim of the study was to determine vitamin D and polyunsaturated fatty acids in colorectal cancer patients., Patients and Methods: A total of 39 patients with colorectal cancer (mean ± SD age: 65.5 ± 6.8 years) and 25 controls (mean ± SD age: 51.0 ± 6.9 years) were studied. 25-hydroxycholecalciferol-25(OH)D 3 in serum was quantitatively determined by high-performance liquid chromatography (HPLC). Levels of linoleic acid (LA) and arachidonic acid (AA) of serum phospholipids were measured by gas-chromatography (GC). Expression of VDR and COX-2 in normal colonic mucosa and tumour tissue was measured by real time polymerase chain reaction (RT-PCR)., Results: The mean value of 25(OH)D 3 was significantly lower in the colorectal cancer patients with early stages of the disease and in patients with tumour confined to the rectum compared to control group (p < 0.02, p < 0.03, respectively). The higher concentration of AA (patients with early stages of the disease) and lower concentration of LA (patients with the advanced stages of the disease) was noticed compared to the control group. For the patients with the early stages of the disease the higher mean fold change of mRNA VDR and the lower mean fold change of mRNA COX-2 was noticed (p < 0.03, p < 0.02, respectively)., Conclusion: The assessment of vitamin D status in patients with colorectal cancer should include measurement of mRNA VDR expression in tumour tissue., (Copyright © 2019 Pan-Arab Association of Gastroenterology. Published by Elsevier B.V. All rights reserved.)

Quercetin has been widely found to exhibit anticancer activity with low toxicity and prevalence in foods. Quercetin has been reported to inhibit digestive system cancers including pancreatic cancer (PAAD) and colon cancer (COAD), but rectal cancer (READ) has not been reported. The reported mechanisms and targets are divergent. In this study, new targets and mechanisms were predicted for the influence of quercetin on PAAD, COAD, and READ using bioinformatics methods. The results showed that quercetin may target CD36 and reduce the death rate caused by PAAD by enhancing the cell adhesion, mediating the uptake of fatty acids (FAs), regulating thrombospondin-1, and stimulating the immune response. Quercetin may lower the death rate from READ by targeting SLCO1B1 and producing enhanced effects from use of this compound, inhibiting cell growth, and inducing apoptosis in tumor cells. ACADS, ALDH3B2, UGT2A3, AMH, CDKN2A, FOSL1, CD36, CFL2, CYP3A4, and MAF were identified as targets for quercetin to reduce the death rate caused by COAD. Glutathione metabolism was mainly involved in the effect of quercetin on COAD, including the enhancement of the oxidation of fatty acids, the metabolism of anticancer medications, and the stiffness of cells, and the reduction of chemical carcinogenesis, the level of anti-Müllerian hormone, the proliferation of cancer cells and transcriptional misregulation, and mediation of the activity of glutathione transferases. The combined analyses of three databases can be referred to and used to seek medications and targets that can be applied to other diseases.

Neoadjuvant concurrent chemoradiotherapy (CCRT), followed by radical proctectomy, is the standard treatment for locally advanced rectal cancer. However, a poor response and therapeutic resistance continue to occur despite this treatment. In this study, we analyzed the microarray datasets (GSE68204) of rectal cancer from the Gene Expression Omnibus database, and identified CHD4 as one of the most significantly up-regulated genes among all subunits of the nucleosome remodeling and histone deacetylation (NuRD) complex, in non-responders to CCRT, among locally advanced rectal cancer (LARC) patients. We confirmed the predictive and prognostic significance of CHD4 expression in CCRT treatment, and its correlation with other clinicopathological features, such as tumor regression grade (TRG), therapeutic response, and patient survival. This was carried out by immunohistochemical studies on endoscopic biopsy tissues from 172 rectal cancer patients, receiving neoadjuvant concurrent chemoradiotherapy (CCRT). A high expression of CHD4 was significantly associated with pre-treatment tumor status ( p < 0.001) and lymph node metastasis ( p < 0.001), post-treatment tumor status ( p < 0.001), and lymph node metastasis ( p < 0.001), vascular invasion ( p = 0.042), and tumor regression grade ( p = 0.001). A high expression of CHD4 could also predict poor disease-specific survival and metastasis-free survival (log-rank test, p = 0.0373 and p < 0.0001, respectively). In multivariate Cox proportional-hazards regression analysis, CHD4 overexpression was an independent factor of poor prognosis for metastasis-free survival (HR, 4.575; 95% CI, 1.717-12.192; p = 0.002). By in vitro studies, based on cell line models, we also demonstrated that, the overexpression of CHD4 induced radio-resistance in microsatellite instability-high (MSI-H) colorectal cells (CRCs). On the contrary, the knockdown of CHD4 enhanced radiosensitivity in microsatellite stable (MSS) CRCs. Altogether, we have identified CHD4 as an important regulator of radio-resistance in both MSI-H and MSS CRC cell lines.

Purpose: To explore whether the Rho protein is involved in the radioresistance of colorectal cancer and investigate the underlying mechanisms., Methods and Materials: Rho GTPase expression was measured after radiation treatment in colon cancer cells. RhoB knockout cell lines were established using the CRISPR/Cas9 system. In vitro assays and zebrafish embryos were used for analyzing radiosensitivity and invasive ability. Mass cytometry was used to detect RhoB downstream signaling factors. RhoB and Forkhead box M1 (FOXM1) expression were detected by immunohistochemistry in rectal cancer patients who participated in a radiation therapy trial., Results: RhoB expression was related to radiation resistance. Complete depletion of the RhoB protein increased radiosensitivity and impaired radiation-enhanced metastatic potential in vitro and in zebrafish models. Probing signaling using mass cytometry-based single-cell analysis showed that the Akt phosphorylation level was inhibited by RhoB depletion after radiation. FOXM1 was downregulated in RhoB knockout cells, and the inhibition of FOXM1 led to lower survival rates and attenuated migration and invasion abilities of the cells after radiation. In the patients who underwent radiation therapy, RhoB overexpression was related to high FOXM1, late Tumor, Node, Metastasis stage, high distant recurrence, and poor survival independent of other clinical factors., Conclusions: RhoB plays a critical role in radioresistance of colorectal cancer through Akt and FOXM1 pathways., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Cancer metabolism is an attractive target of the therapeutic strategy for cancer. The present study identified bouchardatine (Bou) as a potent suppressor of rectal cancer growth by cycle-arresting independent of apoptosis. In cultured HCT-116 rectal cancer cells, Bou increased glucose uptake/oxidation and capacity of mitochondrial oxidation. These effects were associated with an upregulation of uncoupling protein 2 (UCP2) and the activation of its upstream Sirtuin 1 (SIRT1)/(Liver kinase B1) LKB1- (Adenosine monophosphate-activated protein kinase) AMPK axis. The pivotal role of UCP2 in the cancer-suppressing effect was demonstrated by overexpressing UCP2 in HCT-116 cells with similar metabolic effects to those produced by Bou. Interestingly, Bou activated peroxisome proliferators activated receptor γ coactivator 1α (PGC-1α) and recruited it to the promoter of UCP2 in HCT-116 cells along with deacetylation (thus activation) by SIRT1. The requirement of SIRT1 for the cancer-suppressing effect through the PGC-1α-UCP2 was confirmed by the reciprocal responses to Bou in HCT-116 with defected and overexpressed SIRT1. Whereas knockdown, mutation or pharmacological inhibition of SIRT1 all abolished Bou-induced deacetylation/activation of PGC-1α, the opposing effects were observed after overexpressing SIRT1. In mice, administration of Bou (50 mg/kg) also suppressed the growth of rectal cancer associated with increases the UCP2 expression and mitochondria capacity in the tumor. Collectively, our findings suggest that Bou has a therapeutic potential for the treatment of rectal cancer by disrupting the metabolic path of cancer cells via activating the PGC-1α-UCP2 axis with SIRT1 as its primary target., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Prognostication of patients with colorectal cancer (CRC) currently relies on tumor-node-metastasis (TNM) staging but clinical outcomes of patients of the same histoclinical stage are heterogeneous. It is therefore imperative to devise novel molecular tests to stratify CRC patients. Our previous work demonstrated that eukaryotic elongation factor-2 kinase (EEF2K) is a tumor suppressor in CRC. Herein, we investigated EEF2K expression in CRC and determined its relationship with clinicopathological parameters., Methods: Quantitative RT-PCR and Westerns blots were used to examine EEF2K expression in primary tumor and the adjacent non-tumor tissues of CRC patients (n = 20). Kaplan-Meier curves and Cox regression analysis were used to assess the association between clinical outcomes of CRC patients and EEF2K protein expression determined by immunohistochemistry on tissue microarray (n = 151)., Results: EEF2K was significantly downregulated at both mRNA and protein levels in tumors of CRC patients. Univariate Cox regression analysis revealed that CRC patients with high tumor grade, advanced TNM staging and low EEF2K expression were associated with worse overall survival. Multivariate analysis further demonstrated that low EEF2K expression was an independent factor for predicting poorer overall survival in CRC patients (p = 0.014; Hazard ratio = 2.951; 95% confidence interval: 1.240-7.024). The 5-year survival rate was 82.8% in the EEF2K-high-expression group versus 63.9% in the EEF2K-low-expression group (p = 0.0118). The association of overall survival with EEF2K expression in CRC patients was verified in The Cancer Genome Atlas (TCGA) cohort., Conclusions: EEF2K is downregulated in CRC and its expression can be employed as a prognostic marker for CRC patients independent of TNM staging.

Although nuclear immunostaining for paired box protein (PAX5) is widely used in practice, its cytoplasmic localization has not been evaluated. Recently we encountered cytoplasmic granular PAX5 staining in rectal well-differentiated neuroendocrine tumor (WD-NET) in the absence of nuclear staining. We investigated the specificity of this staining pattern for rectal NET (n=21) in comparison with 108 NETs, 1 WD rectal NET with elevated proliferation (WD-NET G3), and 40 poorly differentiated neuroendocrine carcinomas from the gastrointestinal and pancreatobiliary tract and liver. Representative tumor sections were subject to immunohistochemical stain for PAX5 antibody. Immunohistochemistry for 3 L-cell markers, glucagon-like peptide 1 and 2, and peptide YY, was performed on all rectal and appendiceal NETs and all other NETs with cytoplasmic PAX5 staining. Cytoplasmic PAX5 staining was observed in 90% (19/21) of rectal NET, 27% (3/11) of appendiceal, 14% (2/14) of pancreatic, 7% (2/29) of lung, 25% (3/12) metastatic NET in the liver, and 100% (1/1) of renal NET. No PAX5 cytoplasmic staining was seen in all grades of NET in other organs, rectal WD-NET G3, and all neuroendocrine carcinoma. L-cell marker staining was observed in all 21 (100%) rectal, in 3 of 3 (100%) PAX5-positive, and 1 of 7 (14%) PAX5-negative appendiceal NET. Cytoplasmic PAX5 staining is specific for rectal carcinoids. The sensitivity and specificity of PAX5 to detect L-cell type rectal carcinoids is 90% (19/21) and 100% (21/21), respectively. Cytoplasmic localization of the PAX5 protein may be utilized as a surrogate marker to detect L-cell type rectal carcinoids.

Aim: To evaluate the pattern of tumor relapse of pathological complete response (pCR) patients with locally advanced rectal cancer (LARC) following neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME), and to identify predictive factors of distant metastasis in pCR patients after nCRT., Method: This was a retrospective analysis of 118 LARC patients who achieved a pCR following nCRT and TME from 2008 to 2015. Clinicopathological and therapeutic parameters were evaluated as possible predictors of distant metastasis-free survival (DMFS), and COX regression analysis was performed., Results: After a median follow-up of 57 months, the 5-year overall and disease-free survival rates were 94.7% and 88.1%, respectively. Overall, 6 patients (5.1%) died, no local recurrence occurred, 13 patients (11%) developed distant metastases, including lung (n = 5), liver (n = 2), bone (n = 3), lung and brain (n = 1), peritoneal (n = 1), and spleen (n = 1) metastasis. On univariate analysis, tumor distance from the anal verge (HR = 0.706, P = 0.039), acellular mucin pools (HR = 6.687, P = 0.002), and MUC1 expression (HR = 8.280, P < 0.001) were independently associated with DMFS. COX regression demonstrated that MUC1 expression (HR = 3.812, P = 0.041) remained to be an independent predictor of DMFS in pCR patients., Conclusion: Distant metastasis still remained a major concern in pCR patients following nCRT and TME. Tumor distance from the anal verge, acellular mucin pools, and MUC1 expression were associated with distant metastasis in patients with pCR. MUC1 staining remained to be an independent risk factor for DMFS. Such information could facilitate treatment decision in these patients, such as adjuvant chemotherapy and follow-up., (Copyright © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Purpose: The purpose of this study was to evaluate treatment response to neoadjuvant chemoradiotherapy (CRT) with regard to mucin status in pathology and pretreatment magnetic resonance imaging (MRI) in locally advanced rectal cancer., Materials and Methods: Between 2003 and 2011, 306 patients with locally advanced rectal cancer received neoadjuvant CRT followed by surgery, and mucinous adenocarcinoma (MAC) was found in 27 (8.8%). All MAC patients had MRI before and after CRT and mucin proportion at MRI was measured. Therapeutic response was assessed by pathology after total mesorectal excision. To determine the optimal cut-off for mucin proportion in predicting good CRT response (near total or total regression) and negative circumferential resection margin (CRM), the receiver-operating characteristic analysis was performed., Results: After neoadjuvant CRT, overall downstaging occurred in 44.4% of MAC and 72.4% of non-MAC (p=0.001), and positive CRM (≤1 mm) was observed more frequently in MAC (p<0.001). The optimal threshold for treatment response was 30% for mucin proportion, and there are nine with low mucin proportion (<30%) and 18 with high mucin proportion (≥30%) in pretreatment MRI. Negative CRM and tumor downstaging occurred more common in patients with mucin <30%, although statistically insignificant (p=0.071 and p=0.072, respectively). Regarding oncologic outcomes, lower mucin proportion in pretreatment MRI was associated with better disease-free and overall survival in MAC group (p=0.092 and 0.056, respectively), but the difference did not reach statistical significance., Conclusion: Poor treatment outcome with neoadjuvant CRT was observed in patients with MAC, especially those with high mucin proportion at pretreatment MRI.

Background: Rectal adenocarcinoma (READ) is one of the deadliest malignancies, and the molecular mechanisms underlying the initiation and development of READ remain largely unknown. In this study, we aimed to find key long noncoding RNAs (lncRNAs) and mRNAs in READ by RNA sequencing., Methods: RNA sequencing was performed to identify differentially expressed mRNAs (DEmRNAs) and lncRNAs (DElncRNAs) between READ and normal tissue. READ-specific protein-protein interaction (PPI), DElncRNA-DEmRNA coexpression, and DElncRNA-nearby DEmRNA interaction networks were constructed. DEmRNAs and DEmRNAs coexpressed with DElncRNAs were functionally annotated., Results: A total of 2113 DEmRNAs and 150 DElncRNAs between READ and normal tissue were identified. The PPI network identified several hub proteins, including CDK1, AURKB, CDC6, FOXQ1, NUF2, and TOP2A. The DElncRNA-DEmRNA coexpression and DElncRNA-nearby DEmRNA interaction networks identified some hub lncRNAs, including CCAT1, LOC105374879, GAS5, and B3GALT5-AS1. The colorectal cancer pathway, the intestinal immune network for IgA production and the p53 signaling pathway were three pathways significantly enriched in DEmRNAs and DEmRNAs coexpressed with DElncRNAs. MSH6 coexpressed with two DElncRNAs (LOC105374879 and CASC15) and BCL2 coexpressed with B3GALT5-AS1 were significantly enriched in the colorectal cancer signaling pathway. TNFRSF17 coexpressed with B3GALT5-AS1 was enriched in the intestinal immune network for IgA production. CCNB2 coexpressed with LOC105374879 was enriched in the p53 signaling pathway., Conclusion: A total of four DEmRNAs (MSH6, BCL2, TNFRSF17, and CCNB2) and three DElncRNAs (LOC105374879, CASC15, and B3GALT5-AS1) may be involved in the pathogenesis of READ; this data may contribute to understanding the mechanisms of READ and the development of therapeutic strategies for READ., (© 2019 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: Management of neuroendocrine tumors (NETs) depends on the primary site, but the location of many well-differentiated (WD) NETs is elusive. Organ-specific markers are required for pathological diagnosis from biopsy. Transcription factors with good organ specificity include TTF1 (thyroid transcription factor 1; lung), CDX2 (caudal type homeobox transcription factor 2; midgut), and ISL1 (ISL LIM homeobox 1) and PAX8 (paired box 8) for the pancreas and rectum. SATB2 (SATB homeobox 2) has shown high sensitivity and specificity in colorectal adenocarcinoma. This study determined the viability of SATB2 and other transcription factors as markers, single or in combination, for WD-NETs of various sites., Methods: Immunohistochemical staining of 81 WD-NETs from 8 organ sites was performed to identify SATB2, TTF1, CDX2, ISL1, and PAX8. Receiver operating characteristic (ROC) curves were constructed for different combinations of the 5 markers to determine sensitivity and specificity., Results: Among the WD-NETs, SATB2 was predominantly found in those of the rectum; TTF1 in the lung, larynx, and esophagus; and ISL1 in the duodenum and rectum. PAX8 and CDX2 showed poor organ specificity. ROC profiles showed 50% sensitivity and 96% specificity to lung for TTF1 + ISL1-; and 65% sensitivity and 100% specificity to rectum for SATB2 + ISL1- TTF1-. ISL1 + SATB2- TTF1- showed 83% sensitivity and 85% specificity to the duodenum, and 44% sensitivity and 87% specificity to the pancreas. A literature search showed that there was no significant difference in the expression rates of the five transcription factors (TTF1, CDX2, SATB2, PAX8 and ISL1) between primary and metastatic WD-NETs at the same organ when there was a large sample size., Conclusion: Among the 5 transcription factors tested, SATB2 may be a viable marker of WE-NETs of the rectum. The combination of SATB2, ISL1, and TTF1 may help estimate the locations of WD-NETs of unknown origin., (Copyright © 2019. Published by Elsevier GmbH.)

Most patients with locally advanced rectal cancer (LARC) present incomplete pathological response (pIR) to neoadjuvant chemoradiotherapy (nCRT). Despite the efforts to predict treatment response using tumor-molecular features, as differentially expressed genes, no molecule has proved to be a strong biomarker. The tumor secretome analysis is a promising strategy for biomarkers identification, which can be assessed using transcriptomic data. We performed transcriptomic-based secretome analysis to select potentially secreted proteins using an in silico approach. The tumor expression profile of 28 LARC biopsies collected before nCRT was compared with normal rectal tissues (NT). The expression profile showed no significant differences between complete (pCR) and incomplete responders to nCRT. Genes with increased expression (pCR = 106 and pIR = 357) were used for secretome analysis based on public databases (Vesiclepedia, Human Cancer Secretome, and Plasma Proteome). Seventeen potentially secreted candidates (pCR = 1, pIR = 13 and 3 in both groups) were further investigated in two independent datasets (TCGA and GSE68204) confirming their over-expression in LARC and association with nCRT response (GSE68204). The expression of circulating amphiregulin and cMET proteins was confirmed in serum from 14 LARC patients. Future studies in liquid biopsies could confirm the utility of these proteins for personalized treatment in LARC patients.

Localization of rectal tumors is a challenge in minimally invasive surgery due to the lack of tactile sensation. We had developed liposomal indocyanine green (Lip-ICG) for localization of rectal tumor. In this study we evaluated the effects of liposome size and lipid PEGylation on imaging. We used an endoscopically-guided orthotopic experimental rectal cancer model in which tumor fluorescence was determined at different time points after intravenous (i.v.) administration of Lip-ICG and PEGylated liposomes (PEG-Lip-ICG). Signal intensity was measured by tumor-to-background ratio (TBR), or normalized TBR (compared to TBR of free ICG). Fluorescence microscopy of tumor tissue was performed to determine fluorescence localization within the tissue and blood vessels. Liposomes of 60 nm showed an increased TBR compared with free ICG at 12 hours after i.v. injection: normalized TBR (nTBR) = 3.11 vs. 1, respectively (p = 0.006). Larger liposomes (100 nm and 140 nm) had comparable signal to free ICG (nTBR = 0.98 ± 0.02 and 0.78 ± 0.08, respectively), even when additional time points were examined (0.5, 3 and 24 hours). PEG-Lip- ICG were more efficient than Lip-ICG (TBR = 4.2 ± 0.18 vs. 2.5 ± 0.12, p < 0.01) presumably because of reduced uptake by the reticulo-endothelial system. ICG was found outside the capillaries in tumor margins. We conclude that size and lipid modification impact imaging intensity.

Neoadjuvant chemoradiotherapy (nCRT) has been widely applied to improve the local control rate and survival rate in patients with locally advanced rectal cancer (LARC), yet only part of LARC patients would benefit from nCRT. Therefore, it is imperative to predict the therapeutic outcome of nCRT. Here, we showed that RAD18, an E3 ubiquitin-linked enzyme, played a fundamental role in predicting the response of LARC patients to nCRT. According to clinical data, patients with low RAD18 expression level in their pre-nCRT biopsies had a superior response to nCRT compared to those with high RAD18 expression. Inhibition of RAD18 expression in rectal cancer cells pronouncedly attenuated the proliferation and promoted apoptosis after exposing to irradiation or/and 5-fluorouracil (5-Fu). Downregulated RAD18 levels increased cell apoptosis by activating caspase-9-caspase-3-mediated apoptotic pathway, thus resulting in the enhancement of cell radiosensitivity and 5-Fu susceptibility. Furthermore, a xenograft nude mouse model showed that silencing RAD18 significantly slowed tumor growth after irradiation or/and 5-Fu in vivo. Collectively, these results implied that RAD18 could be a new biomarker to predict LARC patients who might benefit from nCRT and provide new strategies for clinical treatment of LARC., (© 2019 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Rectal cancer represents one third of the colorectal cancers that are diagnosed. Neoadjuvant chemoradiation is a well-established protocol for rectal cancer treatment reducing the risk of local recurrence. However, a pathologic complete response is only achieved in 10-40% of cases and the mechanisms associated with resistance are poorly understood. To identify potential targets for preventing therapy resistance, a proteomic analysis of biopsy specimens collected from stage II and III rectal adenocarcinoma patients before neoadjuvant treatment was performed and compared with residual tumor tissues removed by surgery after neoadjuvant therapy. Three proteins, Ku70, Ku80, and Rab5C, exhibited a significant increase in expression after chemoradiation. To better understand the role of these proteins in therapy resistance, a rectal adenocarcinoma cell line was irradiated to generate a radiotherapy-resistant lineage. These cells overexpressed the same three proteins identified in the tissue samples. Furthermore, radiotherapy resistance in this in vitro model was found to involve modulation of epidermal growth factor receptor (EGFR) internalization by Rab5C in response to irradiation, affecting expression of the DNA repair proteins, Ku70 and Ku80, and cell resistance. Taken together, these findings indicate that EGFR and Rab5C are potential targets for the sensitization of rectal cancer cells and they should be further investigated. KEY MESSAGES: • Rab5C orchestrates a mechanism of radioresistance in rectal adenocarcinoma cell. • Rab5C modulates EGFR internalization and its relocalization to the nucleus. • In the nucleus, EGFR can modulate the expression of the DNA repair proteins, Ku70 and Ku80. • Rab5C, Ku70, and Ku80 are overexpressed in tumor tissues that contain tumor cells that are resistant to chemoradiation treatment.

Biomarkers that predict tumor response before surgical treatment are necessary to help select patients for preoperative chemoradiotherapy for rectal cancer. However, no definite predictive biomarker has been established. This study explored programmed death-ligand 1 (PD-L1), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), p-signal transducer and activator of transcription 3 (p-STAT3), and death-domain associated protein as predictive biomarkers with regard to preoperative chemoradiotherapy in rectal cancer.Formalin-fixed paraffin-embedded cancer tissues from pretreatment biopsies from 31 patients who underwent preoperative chemoradiotherapy were studied. The biomarkers were evaluated by immunohistochemistry.PD-L1 positivity was found in 22.6% of 31 patients and complete response (CR) showed 33.3% and non-CR showed 18.2%. EGFR positivity was found in 71.0% of 31 patients and CR showed 88.9% and non-CR showed 73.6%. VEGF positivity was found in 83.9% of 31 patients and CR showed 88.9% and non-CR showed 81.8%. p-STAT3 positivity was found in 80.6% of 31 patients and CR showed 88.9% and non-CR showed 77.3%. On multiple logistic regression analysis, only VEGF expression was found to be a significant predictive factor for CR (P = .001). VEGF expression in pretreatment biopsies might be a predictive marker for CR after preoperative chemoradiation in rectal cancer.Although there is a restriction of small sample size, our finding suggested that this study can be foundation for a larger further study for biomarkers which can predict neoadjuvant therapy response of specimens obtained for diagnosis before surgery.

Background/aim: Recent studies have shown a marked increase of AT-rich interactive domain 3A (ARID3A) in colon cancer tissue compared to normal colon mucosa. However, the role of ARID3A has not yet been determined in rectal cancer. We, therefore, investigated the clinical relevance of ARID3A expression in patients with residual rectal cancer after neoadjuvant chemoradiotherapy (NACRT)., Materials and Methods: One hundred thirty-four patients who underwent surgical resection for residual rectal cancer after NACRT were analyzed. ARID3A expression was evaluated using immunohistochemistry on whole-tissue sections. KRAS exon 2 (codons 12 and 13) and BRAF V600E mutation status were determined using polymerase chain reaction., Results: ARID3A positivity was found in 91 cases (64.5%), and it correlated with absence of perineural invasion (p=0.031), longer disease-free survival (DFS) (p=0.048) and cancer-specific survival (CSS) (p=0.006). However, ARID3A positivity was not correlated with KRAS (p=0.231) or BRAF mutation status (p=0.577). In multivariate analysis, ARID3A positivity was independently associated with a favorable CSS (p=0.035), but not DFS (p=0.051)., Conclusion: ARID3A positivity can predict favorable prognosis in patients with residual rectal cancer after NACRT., (Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Objectives: To develop and validate radiomic models in evaluating biological characteristics of rectal cancer based on multiparametric magnetic resonance imaging (MP-MRI)., Methods: This study consisted of 345 patients with rectal cancer who underwent MP-MRI. We focused on evaluating five postoperative confirmed characteristics: lymph node (LN) metastasis, tumor differentiation, fraction of Ki-67-positive tumor cells, human epidermal growth factor receptor 2 (HER-2), and KRAS-2 gene mutation status. Data from 197 patients were used to develop the biological characteristics evaluation models. Radiomic features were extracted from MP-MRI and then refined for reproducibility and redundancy. The refined features were investigated for usefulness in building radiomic signatures by using two feature-ranking methods (MRMR and WLCX) and three classifiers (RF, SVM, and LASSO). Multivariable logistic regression was used to build an integrated evaluation model combining radiomic signatures and clinical characteristics. The performance was evaluated using an independent validation dataset comprising 148 patients., Results: The MRMR and LASSO regression produced the best-performing radiomic signatures for evaluating HER-2, LN metastasis, tumor differentiation, and KRAS-2 gene status, with AUC values of 0.696 (95% CI, 0.610-0.782), 0.677 (95% CI, 0.591-0.763), 0.720 (95% CI, 0.621-0.819), and 0.651 (95% CI, 0.539-0.763), respectively. The best-performing signatures for evaluating Ki-67 produced an AUC value of 0.699 (95% CI, 0.611-0.786), and it was developed by WLCX and RF algorithm. The integrated evaluation model incorporating radiomic signature and MRI-reported LN status had improved AUC of 0.697 (95% CI, 0.612-0.781)., Conclusion: Radiomic signatures based on MP-MRI have potential to noninvasively evaluate the biological characteristics of rectal cancer., Key Points: • Radiomic features were extracted from MP-MRI images of the rectal tumor. • The proposed radiomic signatures demonstrated discrimination ability in identifying the histopathological, immunohistochemical, and genetic characteristics of rectal cancer. • All MRI sequences were important and could provide complementary information in radiomic analysis.

Biomarkers may hold the key towards development and improvement of personalized cancer treatment. For instance, tumour expression of immune system-related proteins may reveal the tumour immune status and, accordingly, determine choice for type of immunotherapy. Therefore, objective evaluation of tumour biomarker expression is needed but often challenging. For instance, human leukocyte antigen (HLA) class I tumour epithelium expression is cumbersome to quantify by eye due to its presence on both tumour epithelial cells and tumour stromal cells, as well as tumour-infiltrating immune cells. In this study, we solved this problem by setting up an immunohistochemical (IHC) double staining using a tissue microarray (TMA) of rectal tumours wherein HLA class I expression was coloured with a blue chromogen, whereas non-epithelial tissue was visualized with a brown chromogen. We subsequently developed a semi-automated image analysis method that identified tumour epithelium as well as the percentage of HLA class I-positive tumour epithelium. Using this technique, we compared HCA2/HC10 and EMR8-5 antibodies for the assessment of HLA class I tumour expression and concluded that EMR8-5 is the superior antibody for this purpose. This IHC double staining can in principle be used for scoring of any biomarker expressed by tumour epithelium.

Background: Obesity is becoming a bigger health problem every year. Current research shows that the obesity-related metabolic problems are strongly associated with visceral fat and not subcutaneous fat. Visceral obesity (VO) is associated with a worse postoperative outcome in multiple fields of abdominal surgery. On the other hand, muscle mass is related to better postoperative outcome. In rectal cancer patients, we studied the influence of visceral obesity and muscle mass on postoperative complications., Methods: The visceral fat area (VFA) and skeletal muscle area (SMA) were determined on preoperative CT scans in 406 patients. The preoperative comorbidity, per-operative outcome and postoperative complications were extracted retrospectively from the patient files. VO was defined as a VFA > 100 cm 2 . Correlations between body composition, postoperative complications and LOS were studied., Results: In our study, 67% of the patients were classified as visceral obese. Mean body mass index (BMI) was higher in the VO group (26.6 ± 3.5 vs 23.5 ± 2.8; p < 0.001). Visceral obese patients had a higher prevalence of cardiac comorbidity (29% vs 13% p = 0.001), hypertension (36% vs 20% p = 0.002) and diabetes mellitus (16% vs 5% p = 0.002). In addition, VO patients had more operative blood loss (431 vs 310 mL; p = 0.008), longer operating time (166 vs 149 min p = 0.003) and more wound infections (14% vs 8% p = 0.048). Visceral obesity was associated with more complications (OR: 1.63 p = 0.043) and longer LOS (risk estimate: 1.18 p = 0.009)., Conclusion: VO patients more often had a history of cardiac disease, hypertension and diabetes mellitus. Visceral obesity correlated with a worse outcome after surgery for rectal cancer.

Previous studies from our group have brought forward the concept of angiogenic regeneration during radiotherapy (RT), as a major cause of RT failure. This process was examined herein in rectal cancer patients undergoing preoperative chemo-radiotherapy. Out of 25 patients with stage II/III rectal adenocarcinoma, 15 had incomplete response (pIR) after preoperative chemo-radiotherapy. The MIB1 proliferation index, the vascular density (VD) assessed with the anti-CD31 antibody and the Hypoxia Inducible Factor HIF1α was assessed. High VD before RT was related with poor local relapse free survival LRFS (p = 0.04), in cases with pIR. Pre-RT values of MIB1 and of HIF1α were not related with LRFS. High MIB1 index and intensification of VD beyond pre-treatment levels in post-RT samples, features indicative of angiogenic regeneration, defined poor LRFS (p = 0.04 and p = 0.0008, respectively). Angiogenic regeneration is strongly related to failure of RT and surgery to control loco-regional disease in rectal cancer patients. Addition of anti-angiogenic agents in the preoperative chemo-radiotherapy regimens may prove beneficial in subgroups of patients.

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery is the standard treatment for locally advanced rectal cancer. Here, we analyzed the impact of local and systemic environments on the tumor response to preoperative chemoradiotherapy in rectal cancer. We recruited 141 patients with rectal cancer treated with nCRT. We evaluated the local tumor environment, including tumor-infiltrating lymphocytes (TILs), intratumor budding (ITB), and the systemic inflammatory environment, including the neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) level. Our finding revealed that tumor regression was significantly associated with the density of CD8+ TILs in the intraepithelial, the presence of ITB, the combination of NLR and CRP (NLR-CRP) value, and the combination of CD8+ intraepithelial TIL (iTIL) density and ITB presence. Moreover, multivariate analysis showed that only the combination of CD8+ iTILs and ITB was an independent predictive factor for the pathological response to nCRT in rectal cancer. Our finding demonstrate that the local tumor environment was a better predictor of the tumor response than the systemic environment and thus provided new insight into screening for patients who are more likely to benefit from cancer treatment., (© 2019 The Author(s).)

Tumour necrosis factor-α-induced protein 8-like 2 (TIPE2) is a tumour suppressor in many types of cancer. However, the mechanism of action of TIPE2 on the growth of rectal adenocarcinoma is unknown. Our results showed that the expression levels of TIPE2 in human rectal adenocarcinoma tissues were higher than those in adjacent non-tumour tissues. Overexpression of TIPE2 reduced the proliferation, migration, and invasion of human rectal adenocarcinoma cells and down-regulation of TIPE2 showed reverse effects. TIPE2 overexpression increased apoptosis through down-regulating the expression levels of Wnt3a, phospho (p)-β-Catenin, and p-glycogen synthase kinase-3β in rectal adenocarcinoma cells, however, TIPE2 knockdown exhibited reverse trends. TIPE2 overexpression decreased autophagy by reducing the expression levels of p-Smad2, p-Smad3, and transforming growth factor-beta (TGF-β) in rectal adenocarcinoma cells, however, TIPE2 knockdown showed opposite effects. Furthermore, TIPE2 overexpression reduced the growth of xenografted human rectal adenocarcinoma, whereas TIPE2 knockdown promoted the growth of rectal adenocarcinoma tumours by modulating angiogenesis. In conclusion, TIPE2 could regulate the proliferation, migration, and invasion of human rectal adenocarcinoma cells through Wnt/β-Catenin and TGF-β/Smad2/3 signalling pathways. TIPE2 is a potential therapeutic target for the treatment of rectal adenocarcinoma., (© 2019 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Purpose: Rectal neuroendocrine neoplasia (NEN) is more common than other NEN origins, but is less commonly metastatic. However, when present, distant disease carries a particularly poor prognosis. Evidence guiding optimal treatment of such patients is lacking. We assessed PRRT outcomes in patients with somatostatin receptor (SSTR) positive metastatic rectal NEN from two referral centres., Methods: Patients treated with PRRT were retrospectively reviewed. Morphologic (RECIST 1.1), SSTR imaging responses and toxicity were assessed 3 months post-PRRT. Kaplan-Meier estimate was used to determine progression-free survival (PFS) and overall survival (OS) from start of PRRT., Results: Twenty-seven consecutive patients (M = 20, age 31-81 years) were reviewed. The majority (70%) had ENETs grade 2 disease (19 patients), three had Grade 3, one Grade 1, and four not documented. Overall, 63% (10/16 patients with available FDG PET/CT) had FDG avid disease. Twenty-six patients were treated for disease progression. Most had 177 Lu-DOTA-octreotate with median cumulative activity of 30 GBq, median four cycles. 14 patients had radiosensitising chemotherapy (5FU or capecitabine). At 3 months post-PRRT, CT disease control rate (DCR) was 96%: partial response was observed in 70% (19/27) and stable disease in 26%. All but one had partial SSTR imaging response. The median PFS was 29 months. Ten patients died, with median overall survival 81 months with a median follow-up of 67 months. Seventeen patients had further treatments after initial PRRT (10 had further cycles of PRRT). Three patients had grade 3 lymphopenia, without significant renal toxicity, MDS or leukaemia., Conclusion: Our results indicate high efficacy and morphologic responses with minimal toxicity and very encouraging survival from PRRT in patients with metastatic rectal NEN despite the adverse prognostic features of this cohort. Further prospective PRRT trials are warranted in this subgroup.

This study aimed to investigate the correlations between diffuse splenic Fluorine-18-fluorodeoxyglucose ( 18 F-FDG) uptake on positron emission tomography/computed tomography (PET/CT) and inflammatory markers and to evaluate the prognostic significance of splenic FDG uptake in rectal cancer patients who underwent curative surgery. We retrospectively analyzed the data from 161 patients who underwent splenic FDG PET/CT staging and subsequent curative surgical resection of rectal cancer between July 2006 and September 2014. The spleen-to-liver uptake ratio (S/L ratio) was calculated by dividing the spleen SUV mean by liver SUV mean . We found significant positive correlations between the S/L ratio and neutrophil-to-lymphocyte ratio (P = 0.013) and platelet-to-lymphocyte ratio (P = 0.007). In a Kaplan-Meier analysis, patients with S/L ratio ≤0.815 had a significantly higher recurrence-free survival rate than those with S/L ratio >0.815 (P = 0.028). Also, patients with S/L ratio ≤0.731 had a significantly higher overall survival rate than those with S/L ratio >0.731 (P = 0.036). In multivariate analysis, higher S/L ratio, as well as male, poor differentiation, higher TNM stage, perineural invasion, and larger tumor size, was independently predictive of cancer recurrence (>0.815 vs ≤0.815, hazard ratio [HR]: 2.04, P = 0.046). With regard to OS, S/L ratio was also an independent prognostic factor for death during follow-up (>0.731 vs ≤0.731, HR: 3.81, P = 0.017). Our results show significant correlations between S/L ratio on PET/CT and systemic inflammatory markers. Further, S/L ratio was an independent prognostic factor for predicting recurrence and death in patient with rectal cancer after curative surgery.

Purpose: To determine the correlation between the parameters of MR diffusion kurtosis imaging (MR-DKI) and mismatch repair gene expression (MMR) for rectal carcinomas., Materials and Methods: Data from 80 patients with rectal carcinoma were analyzed in this prospective study. High-resolution T2WI and DKI (b = 0, 800 and 1600 s/mm2, respectively) were performed. Mean kurtosis (MK) and mean diffusivity (MD) from DKI were measured. MMR-positive expression and HER-2 expression were classified into two groups. For comparison between different grades, the Mann-Whitney U test, receiver operating characteristic curve, and Spearman's correlation analysis were used for statistical analyses., Results: The MK values in identifying positive MMR expressions (MLH1, MSH2, and MSH6) were more reliable than the MD values (rs value: 0.772 vs. 0.448, 0.733 vs. 0.499, and 0.828 vs. 0.633 respectively, P<0.01). Receiver operating curve analysis showed that the performances of the MK values were better than those of the MD values (z = 2.835, 2.000, and 2.827, respectively, P<0.05), while the performances of the MK and MD-MK values were not statistically significant (z = 0.808, 1.557, and 0.596, respectively, P>0.05). Similarly, MK values were better than MD values in identifying HER2 expression (z = 2.795, P<0.05)., Conclusions: MK derived from DKI demonstrated a greater correlation than MD with MMR expression. It also showed better performance in differentiating between high- and low-grade positive MMR expression and HER2 expression. Thus, DKI may be valuable for the prognoses and evaluation of non-invasive therapies., Competing Interests: The authors have declared that no competing interests exist.

The expression of programmed cell death 1 ligand 1 (PD-L1) and interferon-γ (IFN-γ) is of great interest for the development of chemoradiotherapy and immune checkpoint inhibitor treatments. Patients with nodal metastasis (pN+) tend to have a poor prognosis, even after neoadjuvant chemoradiotherapy (neoCRT) and surgical treatment. In this study, we examined the roles of tumor PD-L1 and IFN-γ before and after neoCRT in locally advanced rectal cancer (LARC) patients. Our results demonstrate that patients with high PD-L1 expression in post-neoCRT tissues exhibit improved 5-year disease-free survival (DFS) and overall survival (OS) compared with those with low PD-L1 expression (p < 0.001). Furthermore, in the pN+ population, patients with high PD-L1 expression in post-neoCRT tissues exhibit improved 5-year DFS and OS. PD-L1 and IFN-γ upregulation increased in tumor tissues after neoCRT, and patients with high PD-L1 and high IFN-γ exhibit improved 5-year DFS and OS (p = 0.04 and p = 0.001, respectively). To the best of our knowledge, this study is the first to demonstrate that PD-L1 upregulation in a pN+ cohort correlates with improved prognosis, which is similar to that in patients without nodal metastasis. Moreover, this study verified that PD-L1 and IFN-γ were upregulated by neoCRT treatment in LARC patients and demonstrated that neoCRT may be useful not only for immune checkpoint inhibitor treatment but also for reinvigorating preexisting anti-cancer immunity.

Objective: To assess the expression levels of exchange protein 1 directly activated by cAMP (Epac1) and phosphodiesterase 4 (PDE4) in rectal carcinoma, and their associations with clinicopathological indexes. In addition, the associations of PDE4 and Epac1 with A-kinase anchor protein 95, connexin 43, cyclin D1, and cyclin E1 were evaluated., Methods: The PV-9000 two-step immunohistochemistry method was used to determine protein expression in 44 rectal carcinoma tissue samples and 16 paracarcinoma tissue specimens., Results: The positive rate of PDE4 protein expression in rectal carcinoma tissues was higher than that of paracarcinoma tissues (59.09% vs. 12.5%, P < 0.05). Similar findings were obtained for Epac1 (55% vs. 6.25%, P < 0.05). No significant associations of PDE4 and Epac1 with degree of differentiation, histological type, and lymph node metastasis were found in rectal carcinoma ( P > 0.05). Correlations between PDE4 and Epac1, PDE4 and Cx43, PDE4 and cyclin E1, and Epac1 and Cx43 were observed (all P < 0.05). There was no correlation between the other protein pairs examined ( P > 0.05)., Conclusion: PDE4 and Epac1 expression levels are increased in rectal carcinoma tissues, suggesting that the two proteins may be involved in the development of this malignancy. Meanwhile, correlations between PDE4 and Epac1, PDE4 and Cx43, PDE4 and cyclin E1, and Epac1 and Cx43 suggested synergistic effects of these proteins in promoting rectal carcinoma.

Background: Disruptor of telomeric silencing 1-like (DOT1L) is a non-SET domain containing methyltransferase known to catalyze mono-, di-, and tri-methylation of histone 3 on lysine 79 (H3K79me). DOT1L-mediated H3K79me has been implicated in chromatin-associated functions including gene transcription, heterochromatin formation, and DNA repair. Recent studies have uncovered a role for DOT1L in the initiation and progression of leukemia and other solid tumors. The development and availability of small molecule inhibitors of DOT1L may provide new and unique therapeutic options for certain types or subgroups of cancer., Methods: In this study, we examined the role of DOT1L in DNA double-strand break (DSB) response and repair by depleting DOT1L using siRNA or inhibiting its methyltransferase activity using small molecule inhibitors in colorectal cancer cells. Cells were treated with different agents to induce DNA damage in DOT1L-depleted or -inhibited cells and analyzed for DNA repair efficiency and survival. Further, rectal cancer patient samples were analyzed for H3K79me3 levels in order to determine whether it may serve as a potential marker for personalized therapy., Results: Our results indicate that DOT1L is required for a proper DNA damage response following DNA double-strand breaks by regulating the phosphorylation of the variant histone H2AX (γH2AX) and repair via homologous recombination (HR). Importantly, we show that small molecule inhibitors of DOT1L combined with chemotherapeutic agents that are used to treat colorectal cancers show additive effects. Furthermore, examination of H3K79me3 levels in rectal cancer patients demonstrates that lower levels correlate with a poorer prognosis., Conclusions: In this study, we conclude that DOT1L plays an important role in an early DNA damage response and repair of DNA double-strand breaks via the HR pathway. Moreover, DOT1L inhibition leads to increased sensitivity to chemotherapeutic agents and PARP inhibition, which further highlights its potential clinical utility. Our results further suggest that H3K79me3 can be useful as a predictive and or prognostic marker for rectal cancer patients.

Primary melanoma involving the anorectal region is rare, accounting for <1% of all melanomas in most Western countries. It characteristically presents at an advanced clinical stage and is associated with poor clinical outcomes. Preliminary reports suggest that response rates to immunotherapies in patients with advanced stage mucosal melanoma are much lower than in cutaneous (or acral) melanoma patients but reasons for this are unclear. Comprehensive characterisation of the immune microenvironment in anorectal melanoma has not previously been performed. A single-institution cohort of 43 primary anorectal melanoma patients was examined to describe clinicopathological features and characterise the immune microenvironment to provide insights into the behaviour of this rare melanoma subtype. The tumours displayed multiple adverse prognostic attributes including deep thickness (median 11.5 mm), ulceration (81%) and high mitotic rate (median 12/mm 2 ). The median overall survival was 24 months and the median recurrence-free survival was 9 months. Tumour-infiltrating lymphocytes (TILs) were absent or mild in most tumours (75%); PD-L1 positive staining (>1% of tumour cells) was present in 44% of cases, however in 86% of positive tumours the percentage of positive cells was ≤10%. Four tumours underwent whole genome sequencing; no ultraviolet signature was identified, and there was a lower mutational load but higher structural chromosomal variant load compared with cutaneous melanomas. Poor responses of anorectal melanomas to immunotherapy may be caused by lower immunogenicity of these tumours as characterised by low mutation burden (and therefore low neoantigenicity), low TILs infiltrates and low PD-L1 expression. Further investigation is required to determine whether TILs and PD-L1 expression predict response to immunotherapy in patients with mucosal melanoma., (Copyright © 2018 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.)

Purpose: To analyze relevant factors for pathological complete remission (pCR) after neoadjuvant therapy for locally advanced rectal cancer., Methods: The clinical data of 531 patients with the American Joint Committee on Cancer (AJCC) stage II or III rectal cancer from January 2014 to December 2017 were retrospectively analyzed. Among these patients, 100 (18.83%) patients achieved pCR. Univariate and multivariate logistic regression analyses were applied to analyze the predictive factors for pCR after neoadjuvant therapy., Results: According to univariate analysis, carcinoembryonic antigen (CEA) before chemo-radiotherapy (CRT) (p=0.021), tumor (T) stage before CRT (p=0.002), interval between the end of CRT and surgery (p<0.001) and maximum depth of tumor invasion before CRT (p=0.039) influenced significantly pCR. Multivariate analysis manifested that the CEA level before CRT [p=0.037, odds ratio (OR) =0.435] and the interval between the end of CRT and surgery (p=0.004, OR=2.864) were significant predictive factors for pCR. Stratified analysis showed that low-level CEA before CRT (p=0.029) affected pCR only in non-smoking group., Conclusions: pCR can be observed in some patients with locally advanced rectal cancer after neoadjuvant therapy. Low-level CEA before CRT and long interval between CRT and surgery are predictive factors for pCR of preoperative neoadjuvant therapy for locally advanced rectal cancer, but low-level CEA is effective in predicting pCR in non-smokers only.

Objective: The objective of the study was to evaluate the usefulness of large-section cytokeratin 20 (CK20) staining technique in the detection of infiltration on the distal wall and mesangial metastasis in patients with middle and lower rectal cancer., Materials and Methods: A total of 62 patients with rectal cancer in the middle and lower segment were studied on large slices stained with CK20. Logistic regression was used to analyze the clinicopathologic factors related to distal low and middle rectal cancer metastasis to the mesorectum and rectal wall., Results: Two types of distal metastasis of the tumor were observed in the rectal wall in 18% (11/62) of the patients: submucosal invasion and muscularis propria invasion. The extent of distal metastasis to the rectal wall was around 0.5-1.0 cm. Four types of distal metastasis occurred in the mesorectum: lymph node invasion, blood and lymphatic vessel invasion, perineural invasion, and isolated neoplastic microfoci. Distal metastasis to the mesorectum was observed in 24% (15/62) of the patients. The extent of metastasis to the mesorectum was around 0.5-4.0 cm. Another three patients with microcapillary invasion in the distal mesorectum were observed by immunohistochemistry, as it was difficult to determine the spread by conventional hematoxylin and eosin staining., Conclusion: The large-section CK20 staining technique is useful for the detection of infiltration on the distal wall and mesangial metastasis in patients with middle and lower rectal cancer., Competing Interests: None

Introduction: Carcinoembryonic antigen (CEA) surveillance is recommended in patients with colorectal cancer for detection of potentially resectable metastases. In patients with appropriate symptoms, a highly increased CEA concentration (> 5 times the upper limit of normal) is considered strongly suggestive of cancer. Despite the recognized value, the test is neither absolutely sensitive nor specific for recurrent cancer. Generally, a greater diagnostic value has been assigned to elevated CEA levels, most commonly greater than 5 ng/mL. Fluctuations within the established normal CEA range are not customarily analyzed., Case Presentations: We report here on 11 patients (8 women, 3 men) who, during the postoperative follow-up period, received a diagnosis of recurrent cancer despite their CEA levels exhibiting very subtle increases. Our cohort shared several similar characteristics such as a nonsmoking status, younger age (median, 52 years at initial diagnosis), and exclusive localization of the cancer to the rectosigmoid region., Discussion: This important clinical observation may expand a prognostic value of CEA in a certain category of patients with colorectal cancer.

Primary melanomas of the anus and rectum are rare neoplasms with aggressive behavior, accounting for 0.1%-4.6% of anal canal tumors. Mucosal melanomas account for approximately 1.2% of all melanomas, of which fewer than 25% are anorectal. Histological evaluation with immunohistochemical stains like HMB-45, S-100, vimentin and Melan A is required for definitive diagnosis. The 5-year survival rate for anorectal melanomas (AM) was reported to be as low as < 20%, in contrast to the value of approximately 80% for cutaneous melanomas. Furthermore, up to 67% of patients are found to have distant metastases at the time of their initial diagnosis with AM. Since the chemotherapy treatment possibilities are limited, patients usually undergo mutation detection tests giving the opportunity of targeted therapy. Herein we report a case of a patient with anorectal melanoma, diagnosed in stage II and the pathomorphological and mutation status finding, together with their correlation to tumor behavior and patient prognosis.

Aim: To identify the candidate marker predicting treatment response and survival outcome in rectal cancer patients who received preoperative chemoradiotherapy (CRT)., Patients and Methods: Between 2000 and 2015, 159 patients with histologically-confirmed rectal adenocarcinoma underwent preoperative CRT followed by surgery. Among them, 70 patients were enrolled and the expression of survivin, cancer stem cell markers (CD44 and CD133) and epithelial-mesenchymal transition markers (E-cadherin and TWIST1) in pretreatment biopsy specimens were evaluated by immunohistochemistry. Associations between the expression of markers and clinical outcomes were evaluated., Results: The median follow-up period of all patients was 71 (range=15-203) months. Five-year overall (OS), disease-free (DFS), locoregional recurrence-free (LRRFS) and distant metastasis-free (DMFS) survival were 80.5%, 60.2% 90.1% and 76.5%, respectively. A significant association between survivin overexpression and worse treatment outcome was shown on univariate analyses for OS, DFS and DMFS (p=0.022, 0.002, and 0.005, respectively). On multivariate analysis, survivin overexpression was an adverse prognosticator for DFS and DMFS (p=0.007 and 0.015, respectively), with a borderline significant trend towards a shorter OS (p=0.069). Four other single biomarkers were not associated with survival outcomes. However, overexpression of both survivin and CD44 was significantly associated with worse OS on multivariate analysis (p=0.003)., Conclusion: Survivin combined with CD44 might be a candidate biomarker for the prediction of recurrence and survival in patients who received preoperative CRT for rectal cancer. Further research with a larger population is needed to validate these results., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Neoadjuvant chemo-radiotherapy is utilized for locally advanced rectal cancer to optimize local control. A subset of patients form mucin pools following radiotherapy but the association between mucin pools and pathological and oncological outcomes following curative proctectomy for rectal cancer remains unknown., Objective: The aim of this study was to determine the significance of mucin pool formation after neoadjuvant chemoradiotherapy for rectal cancer., Methods: This is a retrospective analysis of a prospectively maintained rectal cancer database. Patients who underwent curative proctectomy for rectal cancer following long course chemoradiotherapy between January 2007 and December 2016 were eligible for inclusion., Results: A total of 297 patients were eligible for inclusion; of these 36 (12.1%) had mucin pools on final histopathology. Tumors with mucin pools were less likely to be ypT3/T4 (25.0 vs 51.0%, P = 0.003), were more likely to have a good response (83.3 vs 53.6%, P < 0.001) and more likely to have a pathologic complete response (41.7 vs 19.2%, P = 0.006) to radiotherapy. The presence of mucin pools was associated with less distant recurrence ( P < 0.05) and improved overall survival ( P = 0.02)., Conclusions: The presence of mucin pools following neoadjuvant chemoradiotherapy for rectal cancer represents a surrogate marker of response to treatment and downstaging and is associated with improved survival., (© 2018 Wiley Periodicals, Inc.)

Aim: To establish patient-individual tumor models of rectal cancer for analyses of novel biomarkers, individual response prediction and individual therapy regimens., Methods: Establishment of cell lines was conducted by direct in vitro culturing and in vivo xenografting with subsequent in vitro culturing. Cell lines were in-depth characterized concerning morphological features, invasive and migratory behavior, phenotype, molecular profile including mutational analysis, protein expression, and confirmation of origin by DNA fingerprint. Assessment of chemosensitivity towards an extensive range of current chemotherapeutic drugs and of radiosensitivity was performed including analysis of a combined radio- and chemotherapeutic treatment. In addition, glucose metabolism was assessed with 18 F-fluorodeoxyglucose (FDG) and proliferation with 18 F-fluorothymidine., Results: We describe the establishment of ultra-low passage rectal cancer cell lines of three patients suffering from rectal cancer. Two cell lines (HROC126, HROC284Met) were established directly from tumor specimens while HROC239 T0 M1 was established subsequent to xenografting of the tumor. Molecular analysis classified all three cell lines as CIMP-0/ non-MSI-H (sporadic standard) type. Mutational analysis revealed following mutational profiles: HROC126: APC wt , TP53 wt , KRAS wt , BRAF wt , PTEN wt ; HROC239 T0 M1: APC mut , P53 wt , KRAS mut , BRAF wt , PTEN mut and HROC284Met: APC wt , P53 mut , KRAS mut , BRAF wt , PTEN mut . All cell lines could be characterized as epithelial (EpCAM + ) tumor cells with equivalent morphologic features and comparable growth kinetics. The cell lines displayed a heterogeneous response toward chemotherapy, radiotherapy and their combined application. HROC126 showed a highly radio-resistant phenotype and HROC284Met was more susceptible to a combined radiochemotherapy than HROC126 and HROC239 T0 M1. Analysis of 18 F-FDG uptake displayed a markedly reduced FDG uptake of all three cell lines after combined radiochemotherapy., Conclusion: These newly established and in-depth characterized ultra-low passage rectal cancer cell lines provide a useful instrument for analysis of biological characteristics of rectal cancer., Competing Interests: Conflict-of-interest statement: To the best of our knowledge, no conflict of interest exists.

Introduction: Preoperative chemoradiotherapy (CRT) is a standard treatment for locally advanced rectal cancer patients. Despite the benefits of CRT, its use in non-responder patients can be associated with increased toxicities and surgical resection delay. The identification of CRT response biomarkers, such as microRNAs, could improve the management of these patients. We have studied the microRNA expression in pretreatment endoscopy biopsies from rectal cancer patients treated with CRT to identify potential microRNAs able to predict CRT response and clinical outcome of these patients., Material and Methods: RNA from pretreatment endoscopy biopsies from 96 rectal cancer patients treated with preoperative CRT were studied. Pathological response was graded according to the tumor regression grade (TRG) Dworak classification. In the screening phase, 377 miRNAs were studied in 12 patients with extreme responses (TRG0-1 vs TRG4). The potential role as predictive biomarkers for CRT response, disease-free survival (DFS) and overall survival (OS) of the miRNAs identified in the screening phase were validated in the whole cohort., Results: In the screening phase, an 8-miRNAs CRT-response signature was identified: let-7b, let-7e, miR-21, miR-99b, miR-183, miR-328, miR-375 and miR-483-5p. In the validation phase, miR-21, miR-99b and miR-375 emerged as CRT response-related miRNAs while miR-328 and let-7e emerged as prognostic markers for DFS and OS. Interestingly, ROC curve analysis showed that the combination of miR-21, miR-99b and miR-375 had the best capacity to distinguish patients with maximum response (TRG4) from others., Conclusions: miR-21, miR-99b and miR-375 could add valuable information for individualizing treatment in locally advanced rectal cancer patients., Competing Interests: The authors have declared that no competing interests exist.

Chemoradiotherapy combined with surgical resection is the standard treatment for locally advanced rectal cancer, but not all the patients respond to neoadjuvant treatment. Transforming acidic coiled-coil protein-3 (TACC3) is frequently aberrantly expressed in rectal cancer tissue. In this study, we investigated whether TACC3 could serve as a biomarker predictive of the efficacy of chemoradiotherapy. In all, 152 rectal cancer patients with tumor tissue collected at biopsy and set aside before treatment were enrolled in this study. All patients received chemoradiotherapy and surgical resection. Immunohistochemically detected tumoral TACC3 expression significantly decreased sensitivity to chemoradiotherapy [risk ratio (RR) = 2.236, 95% confidence interval (CI): 1.447-3.456; P = 0.001] and thus the pathological complete response rate ( P = 0.001). TACC3 knockdown using specific siRNA enhanced radiotherapy-induced decreases in proliferation and colony formation by HCT116 and SW480 cells and increased the incidence of radiotherapy-induced apoptosis. Cox multivariate analysis showed that TACC3 was a significant prognostic factor for overall survival ( P = 0.017) and disease-free survival ( P = 0.020). These findings suggest TACC3 expression may be predictive of chemoradiotherapy sensitivity and prognosis in locally advanced rectal cancer.

Colorectal cancer (CRC) onset is profoundly affected by Western diet. Here, we report that high-fat (HF) diet-induced, organ-specific colonic lysine homocysteinylation (K-Hcy) increase might promote CRC onset by impeding DNA damage repair. HF chow induced elevated methionyl-tRNA synthetase (MARS) expression and K-Hcy levels and DNA damage accumulation in the mouse and rat colon, resulting in a phenotype identical to that of CRC tissues. Moreover, the increased copy number of MARS, whose protein product promotes K-Hcy, correlated with increased CRC risk in humans. Mechanistically, MARS preferentially bound to and modified ataxia-telangiectasia and Rad3-related protein (ATR), inhibited ATR and its downstream effectors checkpoint kinase-1 and p53, and relieved cell-cycle arrest and decreased DNA damage-induced apoptosis by disrupting the binding of ATR-interacting protein to ATR. Inhibiting K-Hcy by targeting MARS reversed these effects and suppressed oncogenic CRC cell growth. Our study reveals a mechanism of Western-diet-associated CRC and highlights an intervention approach for reversing diet-induced oncogenic effects., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Background/aim: To determine the most reliable predictor for pathologic complete response (pCR) in patients who underwent preoperative chemoradiotherapy and regional hyperthermia (HCRT) for rectal cancer., Patients and Methods: Thirty-six patients were enrolled. The local control status of the patients was assessed using 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), magnetic resonance imaging (MRI), and colonoscopy before and after HCRT. The relationships between various parameters of these clinical examinations and pCR were analyzed., Results: Ten (28%) patients achieved pCR. The accuracies of predicting pCR using FDG-PET/CT, MRI, and colonoscopy were 78%, 61%, and 75%, respectively. FDG-PET/CT was the only independent predictive modality for pCR (p=0.021). The maximum standardized uptake value (SUV max ) and SUV max normalized to liver uptake (SLR) after HCRT showed the highest sensitivity (90%) and the decreasing rate of SUV max and SLR demonstrated the highest specificity (89%) for pCR., Conclusion: SUV max -based parameters of FDG-PET/CT after HCRT were the most reliable predictors for pCR., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: To analyze the causes and patterns of unexplained carcinoembryonic antigen (CEA) elevation after curative treatment in locally advanced rectal cancer patients., Methods: Among the 1309 locally advanced rectal cancer patients treated with curative resection and radiotherapy between January 2001 and June 2011, 325 patients who postoperatively developed abnormal CEA elevation were reviewed. The unexplained CEA elevation was defined as a CEA level higher than 5 ng/mL with no evidence of cancer recurrence at the time of elevation., Results: Of the 325 patients, 143 (44%) had unexplained CEA elevations. The causes were categorized as delayed recurrence (n = 29, 20%), non-colorectal malignancy (n = 10, 7%), and non-malignancy-related conditions (n = 104, 73%). Shorter intervals between treatment and the first CEA elevation, and a higher peak CEA level, were observed in the delayed recurrence group compared with the non-colorectal malignancy or non-malignancy-related group (intervals of 6.8 vs. 44.9 vs. 23.2 months, respectively, p = 0.002; and peak CEA levels of 9.9 vs. 7.1 vs. 6.2 ng/mL, respectively, p = 0.034). In patients who showed delayed recurrence, the interval between the first CEA elevation and diagnosis of recurrence was a median of 13.0 months (range 3.8-60.6 months). Smoking was the most common cause for non-malignancy-related conditions. The patterns of unexplained CEA elevations were defined as sporadic (n = 78, 55%), stationary (n = 37, 26%), and increasing (n = 28, 20%). The patterns were significantly different depending on the cause (p < 0.001)., Conclusions: Analysis of the patterns of unexplained CEA elevations is a reasonable approach to predict the cause of the cancer.

Objective: To investigate the correlation between c-kit mRNA expression and prognosis in patients with rectal carcinoma. Methods: The expression of c-kit mRNA in rectal carcinoma tissues( n =66) was detected by multiplex branched-DNA liquid chip method. According to the expression level, the patients were classified into the c-kit mRNA high expression group and the low group. We analyzed the relationship between the c-kit mRNA expression and the clinicopathological characteristics of patients, as well as the factors affecting patients'prognosis. Results: Of the 66 rectal carcinoma patients, 18(27.3%)cases were c-kit mRNA high expression. No significant correlation was found between the c-kit mRNA expression and gender, age, preoperative carcinoembryonic antigen, preoperative hemoglobin, distance to verge, lymph node metastasis, tumor thrombus, T stage, TNM stage and tumor differentiation ( P >0.05). In follow-up, 34 patients died, 32 patients and 36 patients were recurrence or metastasis. The 1-, 3-, 5-year overall survival(OS) of c-kit mRNA high expression group were 100.0%, 77.8%, 77.8%, respectively, while those of the low one were 93.8%, 56.3%, 45.8%, respectively. The difference was statistically significant( P =0.025). Lymph node metastasis, T stage and TNM stage were also significant associated with OS( P <0.05). The 1-, 3-, 5-year disease free rate (DFS)of the c-kit mRNA high expression group were 100.0%, 77.8% and 77.8%, respectively, while those of the low one were 77.1%、43.8% and 41.7%, respectively, and the difference between the two groups was significant ( P =0.044). As a reslut, c-kit mRNA expression ( P =0.038) and TNM stage ( P =0.039) were the independent prognostic factors affecting the OS in rectal cancer patients. Conclusions: Low expression of c-kit was associated with poor prognosis of rectal carcinoma. And the mechanism underlying this phenomenon deserves further exploration.

Purpose: The present study aimed to identify a panel of potential metabolite biomarkers to predict tumor response to neoadjuvant chemo-radiation therapy (NCRT) in locally advanced rectal cancer (LARC)., Experimental Design: Liquid chromatography-mass spectrometry (LC-MS)-based untargeted metabolomics was used to profile human serum samples (n = 106) from LARC patients treated with NCRT. The samples were collected from Fudan University Shanghai Cancer Center (FUSCC) from July 2014 to January 2016. Statistical methods, such as partial least squares (PLS) and Wilcoxon rank-sum test, were used to identify discriminative metabolites between NCRT-sensitive and NCRT-resistant patients according to their tumor regression grade (TRG). This trial is registered with Clinical Trials.gov, number NCT03149978., Results: A panel of metabolites was selected as potential predictive biomarkers of pathological response to NCRT. A total of 4810 metabolic peaks were detected, and 57 significantly dysregulated peaks were identified. These 57 metabolic peaks were used to differentiate patients using PLS in a dataset containing NCRT-sensitive (n = 56) and NCRT-resistant (n = 49) patients. The combination of 57 metabolic peaks had AUC values of 0.88, 0.81 and 0.84 in the prediction models using PLS, random forest, and support vector machine, respectively, suggesting that metabolomics has the potential ability to predict responses to NCRT. Furthermore, 15 metabolite biomarkers were identified and used to construct a logistic regression model and explore dysregulated metabolic pathways using untargeted metabolic profiling and data mining approaches., Conclusions: A panel of metabolites has been identified to facilitate the prediction of tumor response to NCRT in LARC, which is promising for the generation of personalized treatment strategies for LARC patients., (Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.)