Subclonal accumulation of immune escape mechanisms in microsatellite instability-high colorectal cancers.

BACKGROUND: Intratumor heterogeneity (ITH) in microsatellite instability-high (MSI-H) colorectal cancer (CRC) has been poorly studied. We aimed to clarify how the ITH of MSI-H CRCs is generated in cancer evolution and how immune selective pressure affects ITH. METHODS: We reanalyzed public whole-exome sequencing data on 246 MSI-H CRCs. In addition, we performed a multi-region analysis from 6 MSI-H CRCs. To verify the process of subclonal immune escape accumulation, a novel computational model of cancer evolution under immune pressure was developed. RESULTS: Our analysis presented the enrichment of functional genomic alterations in antigen-presentation machinery (APM). Associative analysis of neoantigens indicated the generation of immune escape mechanisms via HLA alterations. Multiregion analysis revealed the clonal acquisition of driver mutations and subclonal accumulation of APM defects in MSI-H CRCs. Examination of variant allele frequencies demonstrated that subclonal mutations tend to be subjected to selective sweep. Computational simulations of tumour progression with the interaction of immune cells successfully verified the subclonal accumulation of immune escape mutations and suggested the efficacy of early initiation of an immune checkpoint inhibitor (ICI) -based treatment. CONCLUSIONS: Our results demonstrate the heterogeneous acquisition of immune escape mechanisms in MSI-H CRCs by Darwinian selection, providing novel insights into ICI-based treatment strategies.

Impacts of the STING-IFNAR1-STAT1-IRF1 pathway on the cellular immune reaction induced by fractionated irradiation.

Radiotherapy (RT) combined with immune checkpoint inhibitors has recently produced outstanding results and is expected to be adaptable for various cancers. However, the precise molecular mechanism by which immune reactions are induced by fractionated RT is still controversial. We aimed to investigate the mechanism of the immune response regarding multifractionated, long-term radiation, which is most often combined with immunotherapy. Two human esophageal cancer cell lines, KYSE-450 and OE-21, were irradiated by fractionated irradiation (FIR) daily at a dose of 3 Gy in 5 d/wk for 2 weeks. Western blot analysis and RNA sequencing identified type I interferon (IFN) and the stimulator of IFN genes (STING) pathway as candidates that regulate immune response by FIR. We inhibited STING, IFNAR1, STAT1, and IFN regulatory factor 1 (IRF1) and investigated the effects on the immune response in cancer cells and the invasion of surrounding immune cells. We herein revealed type I IFN-dependent immune reactions and the positive feedback of STING, IRF1, and phosphorylated STAT1 induced by FIR. Knocking out STING, IFNAR1, STAT1, and IRF1 resulted in a poorer immunological response than that in WT cells. The STING-KO KYSE-450 cell line showed significantly less invasion of PBMCs than the WT cell line under FIR. In the analysis of STING-KO cells and migrated PBMCs, we confirmed the occurrence of STING-dependent immune activation under FIR. In conclusion, we identified that the STING-IFNAR1-STAT1-IRF1 axis regulates immune reactions in cancer cells triggered by FIR and that the STING pathway also contributes to immune cell invasion of cancer cells.

Comparative analysis of the immune responses in cancer cells irradiated with X-ray, proton and carbon-ion beams.

Radiotherapy (RT) is an effective treatment option for cancer; however, its efficacy remains less than optimal in locally advanced cancer. Immune checkpoint inhibitor-based therapy, including the administration of anti-PD-L1 antibodies, is a promising approach that works synergistically with RT. Proton beam therapy and carbon-ion therapy are common options for patients with cancer. Proton and carbon ions are reported to induce an immune reaction in cancer cells; however, the underlying mechanisms remain unclear. Here, we aimed to compare the immune responses after irradiation (IR) with X-ray, protons, and carbon ions in an oesophageal cancer cell line and the underlying mechanisms. An oesophageal cancer cell line, KYSE450, was irradiated with 1 fraction/15 GyE (Gy equivalent) of X-ray, proton, or carbon-ion beams, and then, the cells were harvested for RNA sequencing and gene enrichment analysis. We also knocked out STING and STAT1 in the quest for mechanistic insights. RNA sequencing data revealed that gene expression signatures and biological processes were different in KYSE450 irradiated with X-ray, proton, and carbon-ion beams 6-24 h after IR. However, after 3 days, a common gene expression signature was detected, associated with biological pathways involved in innate immune responses. Gene knock-out experiments revealed that the STING-STAT1 axis underlies the immune reactions after IR. X-Ray, proton, and carbon-ion IRs induced similar immune responses, regulated by the STING-STAT1 axis.

Correction: Integrated Multiregional Analysis Proposing a New Model of Colorectal Cancer Evolution.

[This corrects the article DOI: 10.1371/journal.pgen.1005778.].

Integrated Multiregional Analysis Proposing a New Model of Colorectal Cancer Evolution.

Understanding intratumor heterogeneity is clinically important because it could cause therapeutic failure by fostering evolutionary adaptation. To this end, we profiled the genome and epigenome in multiple regions within each of nine colorectal tumors. Extensive intertumor heterogeneity is observed, from which we inferred the evolutionary history of the tumors. First, clonally shared alterations appeared, in which C>T transitions at CpG site and CpG island hypermethylation were relatively enriched. Correlation between mutation counts and patients' ages suggests that the early-acquired alterations resulted from aging. In the late phase, a parental clone was branched into numerous subclones. Known driver alterations were observed frequently in the early-acquired alterations, but rarely in the late-acquired alterations. Consistently, our computational simulation of the branching evolution suggests that extensive intratumor heterogeneity could be generated by neutral evolution. Collectively, we propose a new model of colorectal cancer evolution, which is useful for understanding and confronting this heterogeneous disease.

Serial mutational tracking in surgically resected locally advanced colorectal cancer with neoadjuvant chemotherapy.

BACKGROUND: We aim to investigate the utility of serial gene mutation tracking for locally advanced CRC in those who underwent curative resection following neoadjuvant chemotherapy. METHODS: We prospectively collected 10 locally advanced CRC cases for which curative resection was performed following preoperative neoadjuvant chemotherapy. Tissues from the primary tumour, distant metastatic tumours, and blood plasma were obtained during serial treatment. Comprehensive mutation analysis of 47 cancer-associated genes was performed using a pre-designed gene panel and next-generation sequencing. RESULTS: All cases showed a partial response to neoadjuvant chemotherapy, and pathological R0 resection was accomplished. In primary tumours, non-synonymous mutations were detected at between 1 and 14 sites before chemotherapy and at between 1 and 2 sites after. Founder mutations were precisely detected in blood plasma and metastatic tumours during longitudinal treatment. CONCLUSIONS: Serial mutational analysis indicated that subclonal selection occurs during chemotherapy and that plasma can substitute for tumourous tissue in mutational analysis for drug selection and treatment decisions.

Identification of UHRF2 as a Negative Regulator of Epithelial-Mesenchymal Transition and Its Clinical Significance in Esophageal Squamous Cell Carcinoma.

OBJECTIVE: The involvement of epithelial-mesenchymal transition (EMT) in esophageal squamous cell carcinoma (ESCC) has not been fully elucidated. Here, we aimed to identify EMT-related genes associated with TGF-ß in ESCC and to clarify the role of these genes in the progression of ESCC. METHODS: EMT-related genes associated with TGF-ß expression were identified in patients with ESCC using microarray analysis and public datasets. The effects of ubiquitin-like with PHD and ring finger domains 2 (UHRF2) expression were analyzed in ESCC cell lines. Cell proliferation and invasion were measured using MTT and invasion assays, respectively. UHRF2 mRNA expression was also analyzed in 75 ESCC specimens to determine the clinical significance of UHRF2 in ESCC. RESULTS: Treatment of ESCC cell lines with TGF-ß increased UHRF2 expression. UHRF2 overexpression increased CDH1 (E-cadherin) expression and decreased invasive capacity. The 75 ESCC specimens were divided into the UHRF2 high-expression group (n = 61) and the UHRF2 low-expression group (n = 14). Low UHRF2 expression was significantly correlated with vascular invasion (p = 0.034) and was an independent prognostic factor for poor prognosis (p = 0.005). CONCLUSION: UHRF2 may be a negative regulator of EMT and a novel prognostic biomarker for ESCC.

Genomic Landscape of Esophageal Squamous Cell Carcinoma in a Japanese Population.

BACKGROUND & AIMS: Esophageal squamous cell carcinoma (ESCC) is the predominant form of esophageal cancer in Japan. Smoking and drinking alcohol are environmental risk factors for ESCC, whereas single nucleotide polymorphisms in ADH1B and ALDH2, which increase harmful intermediates produced by drinking alcohol, are genetic risk factors. We conducted a large-scale genomic analysis of ESCCs from patients in Japan to determine the mutational landscape of this cancer. METHODS: We performed whole-exome sequence analysis of tumor and nontumor esophageal tissues collected from 144 patients with ESCC who underwent surgery at 5 hospitals in Japan. We also performed single-nucleotide polymorphism array-based copy number profile and germline genotype analyses of polymorphisms in ADH1B and ALDH2. Polymorphisms in CYP2A6, which increase harmful effects of smoking, were analyzed. Functions of TET2 mutants were evaluated in KYSE410 and HEK293FT cells. RESULTS: A high proportion of mutations in the 144 tumor samples were C to T substitution in CpG dinucleotides (called the CpG signature) and C to G/T substitutions with a flanking 5' thymine (called the APOBEC signature). Based on mutational signatures, patients were assigned to 3 groups, which associated with environmental (drinking and smoking) and genetic (polymorphisms in ALDH2 and CYP2A6) factors. Many tumors contained mutations in genes that regulate the cell cycle (TP53, CCND1, CDKN2A, FBXW7); epigenetic processes (MLL2, EP300, CREBBP, TET2); and the NOTCH (NOTCH1, NOTCH3), WNT (FAT1, YAP1, AJUBA) and receptor-tyrosine kinase-phosphoinositide 3-kinase signaling pathways (PIK3CA, EGFR, ERBB2). Mutations in EP300 and TET2 correlated with shorter survival times, and mutations in ZNF750 associated with an increased number of mutations of the APOBEC signature. Expression of mutant forms of TET2 did not increase cellular levels of 5-hydroxymethylcytosine in HEK293FT cells, whereas knockdown of TET2 increased the invasive activity of KYSE410 ESCC cells. Computational analyses associated the mutations in NFE2L2 we identified with transcriptional activation of its target genes. CONCLUSIONS: We associated environmental and genetic factors with base substitution patterns of somatic mutations and provide a registry of genes and pathways that are disrupted in ESCCs. These findings might be used to design specific treatments for patients with esophageal squamous cancers.

Attenuated RND1 Expression Confers Malignant Phenotype and Predicts Poor Prognosis in Hepatocellular Carcinoma.

BACKGROUND: The RND1 gene encodes a protein that belongs to the Rho GTPase family, which regulates various cellular functions. Depletion of RND1 expression activates the oncogenic Ras signaling pathway. In this study, we aimed to clarify the clinical significance of RND1 expression in predicting prognosis and to investigate its biological role in human hepatocellular carcinoma (HCC). METHODS: The association between RND1 expression and clinical outcomes in patients with HCC was analyzed in three independent cohorts: 120 cases resected in our hospital; 370 cases in The Cancer Genome Atlas (TCGA); and 242 cases in GSE14520. Gene set enrichment analysis (GSEA) was also conducted. Finally, knockdown experiments were performed using small interfering RNA (siRNA) in vitro. RESULTS: In all cohorts, RND1 expression was decreased as cancer progressed, and was affected by promoter methylation. In our HCC cases, the 5-year overall survival (OS) and recurrence-free survival of patients with low RND1 expression was significantly poorer than those of patients with high RND1 expression. TCGA and GSE14520 analyses provided similar results for OS. Multivariate analysis indicated that RND1 expression was an independent prognostic factor for OS in all three cohorts. Additionally, GSEA showed an inverse correlation between RND1 expression and the Ras signaling activity. In vitro, knockdown of RND1 expression resulted in significant increases in proliferation, invasion, and chemoresistance to cisplatin in HCC cells. CONCLUSIONS: Reduced RND1 expression in HCC was associated with cancer progression, likely through regulation of the Ras signaling pathway, and may serve as a novel clinical biomarker for predicting prognosis in patients with HCC.

Altered Expression of Hippo Signaling Pathway Molecules in Intrahepatic Cholangiocarcinoma.

OBJECTIVE: MOB1, a core component of the Hippo signaling pathway, suppresses cell proliferation, and MOB1 liver conditional knockout mice develop intrahepatic cholangiocarcinoma (ICC). However, its clinical significance in human ICC has not been established. The aim of this study was to characterize protein levels and the role of Hippo and TGF pathways in ICCs. METHODS: The protein levels of yes-associated protein 1 (YAP1), MOB1, Smad2, and TGFß2 in 88 ICC cases were analyzed. Protein level was graded by a scoring system; then, the clinicopathological factors, including prognosis, were analyzed based on protein level. RESULTS: Nuclear overexpression of YAP1 was seen in 28 cases (31.8%), and it was significantly associated with a poor overall survival rate (p = 0.01). MOB1 expression decreased in 42 cases (47.7%) and was associated with a poor overall survival rate (p = 0.02). SMAD2 nuclear localization was significantly correlated with a high YAP1 level independent of TGFß2. Multivariate analysis revealed that a high YAP1 level, a low MOB1 level, and lymphatic permeation were independent risk factors for overall survival. CONCLUSIONS: These results showed that key components of the Hippo signaling pathway are aberrantly expressed and associated with the malignant potential of human ICC.

8q24 Polymorphisms and Diabetes Mellitus Regulate Apolipoprotein A-IV in Colorectal Carcinogenesis.

BACKGROUND: Here, we explored the genetic interactions between diabetes and oncogenic single-nucleotide polymorphisms (SNPs) that determine colorectal cancer (CRC) morbidity. METHODS: 8q24 rs6983267 polymorphism analysis and cDNA microarray were performed in 107 CRCs to identify the genes associated with diabetes and the oncogenic SNP. Then clinical significance of the gene was validated in 132 CRCs. Meta-analysis of microarray data and diabetic comorbidity was performed. RESULTS: Of genes associated with a minor SNP allele at 8q24, diabetes, and MYC overexpression, apolipoprotein A-IV (ApoA-IV) was associated with oncogenesis and poor prognosis in CRC patients. Patients with high ApoA-IV expression showed significantly poorer prognosis by univariate and multivariate analysis. Meta-analysis revealed lipid metabolism was associated with ApoA-IV-related oncogenesis in diabetic patients. CONCLUSIONS: Changes in lipid metabolism associated with aberrant expression of ApoA-IV were risks for CRC oncogenesis.

Aberrant Methylation of FOXE1 Contributes to a Poor Prognosis for Patients with Colorectal Cancer.

BACKGROUND: Hypermethylation of DNA silences gene expression and is an important event in colorectal cancer (CRC). This study aimed to identify aberrantly methylated genes that contribute to a poor prognosis for patients with CRC. METHODS: The study comprehensively explored DNA methylation microarray profiles from 396 CRC samples and 45 normal control samples in a database and selected aberrantly methylated transcription factors associated with prognosis and metastasis. Using quantitative reverse transcription polymerase chain reaction, the identified genes in 140 patients with CRC were validated to assess the relationship between expression of methylated genes and prognosis. RESULTS: In the study, FOXE1 was newly identified as a gene associated with prognosis and metastasis in CRC. Expression of FOXE1 in CRC tissues was significantly lower than in normal colorectal tissues (p = 0.01). The survival rate for the patients with low expression of FOXE1 was significantly lower than that for patients with high expression of FOXE1 in uni- and multivariate analyses. Inhibition of DNA methylation recovered FOXE1 expression in CRC cells. CONCLUSIONS: Methylation-mediated silencing of FOXE1 expression was shown to be a potential prognostic factor in CRC.

Downregulation of PRRX1 Confers Cancer Stem Cell-Like Properties and Predicts Poor Prognosis in Hepatocellular Carcinoma.

BACKGROUND: Downregulation of paired related homeobox 1 (PRRX1) is associated with the acquisition of cancer stem cell (CSC)-like properties and poor prognosis in cancers. The purpose of this study is to clarify the role of PRRX1 expression in predicting prognosis and mediating CSC-like properties in hepatocellular carcinoma (HCC). METHODS: The association between PRRX1 expression and overall survival (OS) of patients with HCC was analyzed in three independent datasets: 62 resected primary cases, 242 cases from GSE14520, and 162 cases from The Cancer Genome Atlas (TCGA). A cell line expressing PRRX1 (HuH7) was established for the functional analyses. The ability to form spheres, the expression levels of the hepatic CSC surface markers (CD13, CD133, and EpCAM), in vitro chemosensitivity to 5-fluorouracil (FU), and radiosensitivity were evaluated. RESULTS: Univariate and multivariate analyses showed that the 5-year OS of the low PRRX1 expression group was significantly poorer than that of the high PRRX1 expression group (P = 0.024 and P = 0.045, respectively). Consistent with this, the low PRRX1 expression group in GSE14520 and TCGA datasets showed significantly shorter OS (P = 0.027 and P = 0.010, respectively). Gene set enrichment analysis on GSE14520 and TCGA datasets indicated that downregulation of PRRX1 was correlated with the stemness signature. The number of spheres and the expression levels of CSC markers were significantly decreased when PRRX1 was expressed. Moreover, PRRX1 impaired resistance to 5-FU and radiation. CONCLUSIONS: Downregulation of PRRX1 expression contributes to the poor prognosis of patients with HCC through acquisition of CSC-like properties.

A Long Non-coding RNA Activated by Transforming Growth Factor-ß is an Independent Prognostic Marker of Gastric Cancer.

BACKGROUND: A recent study reported that long non-coding RNA activated by TGF-ß (lncRNA-ATB) induced epithelial-mesenchymal transition (EMT) through the transforming growth factor-ß (TGF-ß)/miR-200s/ZEB axis in hepatocellular carcinoma. Herein, we focused on the clinical significance of lncRNA-ATB in gastric cancer (GC) patients. MATERIALS AND METHODS: Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was performed to examine expression of lncRNA-ATB, miR-200b, and miR-200c in GC tissues (n = 183). Patients were divided into high and low lncRNA-ATB expression groups using a cutoff of lncRNA-ATB/GAPDH ≥0.60 or <0.60 to determine the clinicopathological significance of lncRNA-ATB in GC. Moreover, we evaluated the expression of TGF-ß, lncRNA-ATB, miR-200s, and ZEB1 in GC cell lines by qRT-PCR. GC cell lines were treated by recombinant TGF-ß1 or TGF-ß receptor inhibitor to examine morphologic changes and genetic alterations, such as lncRNA-ATB, miR-200s, and ZEB1 levels, with respect to the EMT phenotype. RESULTS: The high lncRNA-ATB group experienced a lower overall survival rate compared with the low lncRNA-ATB group, and multivariate analysis indicated that lncRNA-ATB was an independent prognostic factor (hazard ratio 3.50; 95 % CI 1.73-7.44; p = 0.0004). miR-200c levels were lower and ZEB1 levels were higher in the high lncRNA-ATB group than in the low lncRNA-ATB group. Treatment with TGF-ß in GC cell lines resulted in morphological EMT changes, upregulation of lncRNA-ATB and ZEB1, and downregulation of miR-200c and CDH1. SB431542 reduced lncRNA-ATB expression. CONCLUSION: LncRNA-ATB plays an important role in EMT to promote invasion and metastasis through the TGF-ß/miR-200s/ZEB axis, resulting in a poor prognosis in GC. LncRNA-ATB is a novel biomarker of lncRNA, indicative of a poor prognosis in GC patients.

Overexpression of Transcription Termination Factor 1 is Associated with a Poor Prognosis in Patients with Colorectal Cancer.

BACKGROUND: RNA polymerase 1 transcription termination factor (TTF1) mediates the transcription of ribosomal RNA (rRNA). In the current study, we investigated the clinical and biological significance of the TTF1 gene in colorectal cancer (CRC). METHODS: The expression of TTF1 messenger RNA (mRNA) in tumor and normal tissues from 136 patients with CRC was examined by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). We also performed in vitro cell proliferation and migration assays in TTF1-expressing CRC cells. The biological role of TTF1 in CRC was further elucidated using gene set enrichment analysis (GSEA) with CRC samples. RESULTS: TTF1 expression was significantly higher in tumor tissues than in corresponding normal tissues (p = 0.016). In clinicopathological analysis, the high-TTF1 expression group showed a higher incidence of liver metastasis and lymphatic invasion than the low-TTF1 expression group (p < 0.05), and tended to have more frequent venous invasion than the low-TTF1 expression group. Furthermore, the high-TTF1 expression group had a significantly poorer prognosis than the low-TTF1 expression group (p = 0.011). Moreover, overexpression of TTF1 enhanced the proliferation and migration capacity of CRC cells in vitro. GSEA revealed that TTF1 was significantly associated with the RAS and MYC pathways, and this observation was confirmed in samples from 136 patients with CRC. CONCLUSION: TTF1 was involved in cancer progression via the RAS and MYC pathways in CRC, suggesting that TTF1 may be a prognostic indicator and therapeutic target in CRC.

The miR-506-Induced Epithelial-Mesenchymal Transition is Involved in Poor Prognosis for Patients with Gastric Cancer.

BACKGROUND: MicroRNAs have roles in the regulation of the epithelial-mesenchymal transition (EMT). Findings have shown that miR-506 inhibits the expression of SNAI2 and that low expression of miR-506 is associated with poor prognoses in ovarian and breast cancers. This study investigated the role of miR-506 in survival and the EMT in patients with gastric cancer. METHODS: In this study, miR-506 and SNAI2 mRNA levels were measured in 141 cases of gastric cancer by quantitative reverse transcription polymerase chain reaction, and the protein expressions of SNAI2 and E-cadherin in 39 cases were validated by immunohistochemical analysis. Next, the associations between their expression levels and clinicopathologic factors were evaluated. In addition, cell proliferation, migration, and luciferase activity of the 3' untranslated region (UTR) of SNAI2 were analyzed using pre-miR-506 precursor in two human gastric cancer cell lines. RESULTS: Low expression of miR-506 was significantly correlated with poor overall survival in both the univariate analysis (P = 0.016) and the multivariate analysis (P < 0.05). Low miR-506 expression was significantly correlated with high SNAI2 expression (P = 0.009) and poorly differentiated type (P = 0.015). In vitro, miR-506 suppressed SNAI2 expression by binding to its 3'UTR, resulting in increased expression of E-cadherin (P < 0.05), verified by immunohistochemical analysis. Pre-miR-506 transfected cells showed significantly suppressed cell proliferation and migration (P < 0.05) compared with the control cells. CONCLUSIONS: The EMT was directly suppressed by miR-506, and its low expression was an independent prognostic factor in gastric cancer patients. The data indicated that miR-506 may act as a tumor suppressor and could be a novel therapeutic agent.

Clinical characteristics and outcome of pneumothorax after stereotactic body radiotherapy for lung tumors.

BACKGOUND: We retrospectively investigated the clinical characteristics and outcome of pneumothorax after stereotactic body radiotherapy (SBRT) for lung tumors. METHODS: Between April 2003 and July 2012, 473 patients with lung tumors were treated with SBRT. We identified 12 patients (2.5 %) with pneumothorax caused by SBRT, and evaluated the clinical features of pneumothorax. RESULTS: All of the tumors were primary lung cancers. The severity of radiation pneumonitis was grade 1 in 10 patients and grade 2 in two patients. Nine patients had emphysema. The planning target volume and pleura overlapped in 11 patients, and the tumors were attached to the pleura in 7 patients. Rib fractures were observed in three patients before or at the same time as the diagnosis of pneumothorax. The median time to onset of pneumothorax after SBRT was 18.5 months (4-84 months). The severity of pneumothorax was grade 1 in 11 patients and grade 3 in one patient. CONCLUSION: Although pneumothorax was a relatively rare late adverse effect after SBRT, some patients demonstrated pneumothorax after SBRT for peripheral lung tumors. Although most pneumothorax was generally tolerable and self-limiting, careful follow-up is needed.

Clinical significance of GAB2, a scaffolding/docking protein acting downstream of EGFR in human colorectal cancer.

PURPOSE: Recent studies indicated that the scaffolding adaptor protein GAB2 (GRB2-associated binding protein 2) plays a critical role in the proliferation and migration of various cancers. This study aimed to determine the role of aberrant GAB2 expression in human colorectal cancer (CRC). METHODS: Quantitative real-time reverse transcription polymerase chain reaction was used to evaluate GAB2 mRNA expression in 152 CRC tissues samples to determine the clinicopathological significance of GAB2 expression. We also performed in vitro proliferation assays using siGAB2-transfected CRC cells. RESULTS: GAB2 expression in tumor colorectal tissues was significantly higher than in normal colorectal tissues (p = 0.0212). High GAB2 expression levels were associated with malignant clinicopathologic potential factors, including lymphatic invasion (p = 0.0003), venous invasion (p = 0.0170), and liver metastasis (p = 0.0144). The survival rate of patients with high GAB2 expression levels was significantly lower than that of patients with low GAB2 expression (p = 0.0074). Multivariate analysis indicated that GAB2 expression was a factor affecting lymph node metastasis. Cell proliferation was significantly suppressed by siGAB2 expression in CRC cells in vitro. CONCLUSIONS: GAB2 expression was associated with lymph node metastasis and may play a role in the growth and metastasis of CRC. These results suggest that GAB2 is a potential therapeutic target in CRC.

Loss of CDCP1 expression promotes invasiveness and poor prognosis in esophageal squamous cell carcinoma.

BACKGROUND: Human CDCP1 gene, located on chromosome 3p21.3, is a transmembrane glycoprotein widely expressed in epithelial tissues, and its role in cancer remains to be understood. METHODS: Using microarray profiles of gene expression and copy number data from 69 esophageal squamous cell carcinoma (ESCC) samples, we performed informatics analyses to reveal the significance of CDCP1 expression. We also performed migration and invasion assays of siRNA-targeted CDCP1-transfected cells and CDCP1-overexpressing cell in vitro. Moreover, we evaluated the clinical magnitude of CDCP1 expression in esophageal squamous cell cancer cases. RESULTS: Allelic loss of chromosome 3p was confirmed by copy number analysis. The expression level of CDCP1 in tumor tissue was significantly lower than that in corresponding normal tissue. siRNA targeting of CDCP1 promoted the migratory and invasive abilities of esophageal cancer cell lines, whereas both abilities were reduced in CDCP1-overexpressing cells. Gene set enrichment analysis showed that expression levels of CDCP1 were associated with tumor differentiation and metastasis, consistent with the result of clinicopathologic analyses. Finally, multivariate analysis revealed that the expression level of CDCP1 was an independent prognostic factor for survival. CONCLUSIONS: Loss of CDCP1 expression may be a novel indicator for biological aggressiveness in ESCC.

Accelerated three-dimensional conformal radiotherapy for early-stage glottic cancer in reducing dose to the internal carotid artery and pharyngeal constrictor muscles.

BACKGROUND: We evaluated clinical and dosimetric outcomes of radiotherapy using two anterior oblique portals (AOP), to reduce the dose to the bilateral internal carotid arteries (CAs) and pharyngeal constrictor muscle (PCM) during early-stage glottic cancer (ESGC) treatment. METHODS: We identified patients with ESGC who underwent definitive radiotherapy between June 2014 and May 2020. RESULTS: Among the 66 patients, 32 (48%) underwent radiotherapy using AOP, and the remaining underwent typical radiotherapy using parallel opposed lateral portals (POLP). The median follow-up duration was 53 months. No significant differences were observed in the 5-year local failure (0%/9.4%), progression-free survival (90.6%/90.8%), and overall survival (90.6%/91.0%) rates between the two groups. The grade ≥2 acute mucositis incidence rate was significantly lower in the AOP group (44%/85%). Radiotherapy using AOP maintained an adequate dose coverage to the target while markedly reducing the CAs and PCM doses. CONCLUSION: Radiotherapy with AOP resulted in favorable clinical and dosimetric outcomes.