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.
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.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The functions of many long non-coding RNAs (ncRNAs) in human cancers have not yet been elucidated. The long ncRNA HOTAIR is expressed from the developmental HOXC locus located on chromosome 12q13.13. ...Previous reports have demonstrated that HOTAIR associates with chromatin modifications in cooperation with the Polycomb complex PRC2, and promotes breast and colorectal cancer metastasis. In this study, we examined the clinical significance of HOTAIR expression in patients with hepatocellular carcinoma (HCC). HOTAIR expression was detected in primary HCCs in 13 out of 64 patients. Patients with HOTAIR expression had significantly poorer prognoses and a larger primary tumor size than those without HOTAIR expression, similar to studies in breast and colorectal cancers. Moreover, introduction of human HOTAIR into liver cancer cells revealed that HOTAIR promoted more rapid proliferation compared to control cells. Thus, although the clinical significance of HOTAIR expression in HCC may not be as pronounced as that in breast and colorectal cancers, the current study demonstrates that HOTAIR expression is associated with HCC progression, warranting further studies.
Cancer-associated fibroblasts (CAFs) have recently been linked to the invasion and metastasis of gastric cancer. In addition, the microRNA (miR)-200 family plays a central role in the regulation of ...the epithelial-mesenchymal transition process during cancer metastasis, and aberrant DNA methylation is one of the key mechanisms underlying regulation of the miR-200 family. In this study, we clarified whether epigenetic changes of miR-200b by CAFs stimulate cancer invasion and peritoneal dissemination in gastric cancer. We evaluated the relationship between miR-200b and CAFs using a coculture model. In addition, we established a peritoneal metastasis mouse model and investigated the expression and methylation status of miR-200b. We also investigated the expression and methylation status of miR-200b and CAFs expression in primary gastric cancer samples. CAFs (CAF-37 and CAF-50) contributed to epigenetic changes of miR-200b, reduced miR-200b expression and promoted tumor invasion and migration in NUGC3 and OCUM-2M cells in coculture. In the model mice, epigenetic changes of miR-200b were observed in the inoculated high-frequency peritoneal dissemination cells. In the 173 gastric cancer samples, the low miR-200b expression group demonstrated a significantly poorer prognosis compared with the high miR-200b expression group and was associated with peritoneal metastasis. In addition, downregulation of miR-200b in cancer cells was significantly correlated with alpha-smooth muscle actin expression. Our data provide evidence that CAFs reduce miR-200b expression and promote tumor invasion through epigenetic changes of miR-200b in gastric cancer. Thus, CAFs might be a therapeutic target for inhibition of gastric cancer.
The placement of a self-expanding metallic stent (SEMS) in obstructive colorectal cancer (OCRC) is acknowledged to be a safe and effective procedure for the relief of obstruction. However, there is ...concern that shear forces acting on the tumor during stent expansion may release cancer cells into the circulation, resulting in a poor prognosis. The aim of the present study was to determine whether colonic stent insertion increases viable circulating tumor cells (v-CTCs). A telomerase-specific replication-selective adenovirus-expressing GFP (TelomeScanF35) detection system was used to detect v-CTCs in 8 OCRC patients with a SEMS before and after stent insertion and after surgical resection. In 7 patients, a SEMS was inserted as a bridge to surgery (BTS), and in one patient, a SEMS was inserted for palliation. Surgical resection (R0) was performed in 7 patients. Four patients had no v-CTCs before SEMS placement, two of four measurable patients had an increased number of v-CTCs after SEMS placement (1-3 v-CTCs), and one of two patients with increased v-CTCs developed distant lymphatic metastasis despite curative resection. Four patients had v-CTCs (1-19 cells) before SEMS placement, and two of these four patients had an increase in the number of v-CTCs (20-21 cells) after SEMS placement, while one of the four patients died early with distant metastasis. The present study demonstrated that endoscopic stent insertion for OCRC may result in tumor cell dissemination into the peripheral circulation and may induce distant metastases.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Peritoneal dissemination is the most frequent, incurable metastasis occurring in patients with advanced gastric cancer (GC). However, molecular mechanisms driving peritoneal dissemination still ...remain poorly understood. Here, we aimed to provide novel insights into the molecular mechanisms that drive the peritoneal dissemination of GC. We performed combined expression analysis with in vivo-selected metastatic cell lines and samples from 200 GC patients to identify driver genes of peritoneal dissemination. The driver-gene functions associated with GC dissemination were examined using a mouse xenograft model. We identified a peritoneal dissemination-associated expression signature, whose profile correlated with those of genes related to development, focal adhesion, and the extracellular matrix. Among the genes comprising the expression signature, we identified that discoidin-domain receptor 2 (DDR2) as a potential regulator of peritoneal dissemination. The DDR2 was upregulated by the loss of DNA methylation and that DDR2 knockdown reduced peritoneal metastasis in a xenograft model. Dasatinib, an inhibitor of the DDR2 signaling pathway, effectively suppressed peritoneal dissemination. DDR2 was identified as a driver gene for GC dissemination from the combined expression signature and can potentially serve as a novel therapeutic target for inhibiting GC peritoneal dissemination.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Background
The importance of mesenchymal characteristics has not been fully elucidated in esophageal cancer.
Methods
Ten normal and 77 tumor specimens were collected. Microarray analysis was ...performed to analyze the expression patterns of epithelial markers, mesenchymal markers, epithelial mesenchymal transition (EMT)-related genes and stem cell markers. RT-PCR analysis was conducted to confirm the results of microarray analysis. Immunohistochemical analysis was performed to verify the level of protein expression. Statistical analysis was performed to investigate the correlation between selected genes and clinicopathological factors.
Results
Microarray analysis showed that epithelial markers were significantly down-regulated whereas mesenchymal markers and EMT transcription factors were up-regulated in cancer cells. Two types of gene expression patterns were found in the clustering analysis, type 1 tumors and type 2 tumors. Type 1 tumor clusters did not reveal a fixed gene expression pattern whereas type 2 tumor clusters revealed up-regulation of mesenchymal markers EMT inducers and related genes. Vimentin and fibronectin were selected to distinguish between tumor types 1 and 2. Type 2 tumors showed significantly larger tumor sizes (
p
< 0.0001), wider ranges of lymph node metastasis (
p
= 0.0057), and a more severe clinical stage (
p
< 0.0001) than did type 1 tumors. The prognosis of patients with type 2 tumors was significantly worse than that of patients with type 1 tumors. Univariate and multivariate analyses revealed that classification of type 2 tumors was an independent prognostic factor.
Conclusions
The analysis of mesenchymal markers in esophageal cancer is useful in distinguishing patients with a poor prognosis.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Integrin-associated protein (CD47) is ubiquitously expressed on the surface of cells and functions as an identifier of self. In blood cancer, tumor cells expressing CD47 evade phagocytosis by ...macrophages, leading to a poor patient prognosis. However, the status of CD47 expression in solid tumors, particularly in gastric cancer, is not well understood. The purpose of the present study was to examine the level of CD47 in the primary tumor, peripheral blood (PB) and bone marrow (BM) of patients with gastric cancer, and to determine its effect. Reverse transcription-quantitative polymerase chain reaction analysis was performed to determine the level of CD47 mRNA expression in primary tumor, PB and BM samples collected from 168 patients with gastric cancer. Cell sorting was performed to investigate CD47 protein expression in PB and BM fractions, and to identify the source of CD47 expression. In primary tumors, the expression of CD47 was not associated with any clinicopathological factors or prognosis. By contrast, in PB, the low CD47 expression group demonstrated a significantly increased tumor size, and frequency of lymphatic invasion and lymph node metastasis, compared with the high CD47 expression group. In addition, the clinical tumor stage of the low CD47 expression group was significantly increased compared with that of the high CD47 expression group. Conversely, in PB, the high CD47 expression group had a significantly higher frequency of lymphatic invasion and lymph node metastasis compared with the low CD47 expression group. The lymphocyte fraction exhibited the highest CD47 expression compared with the other fractions in PB and BM samples. Low expression of CD47 was associated with the advancement of gastric cancer, in contrast to other cancers, and it may be associated with a decrease in lymphocytes during later stages. These results indicate that CD47 expression in the PB and BM may serve as a marker to analyze the immunological function of patients with gastric cancer; however, the significance of CD47 in gastric cancer requires further study.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Few driver genes have been well established in esophageal squamous cell carcinoma (ESCC). Identification of the genomic aberrations that contribute to changes in gene expression profiles can be used ...to predict driver genes.
We searched for driver genes in ESCC by integrative analysis of gene expression microarray profiles and copy number data. To narrow down candidate genes, we performed survival analysis on expression data and tested the genetic vulnerability of each genes using public RNAi screening data. We confirmed the results by performing RNAi experiments and evaluating the clinical relevance of candidate genes in an independent ESCC cohort.
We found 10 significantly recurrent copy number alterations accompanying gene expression changes, including loci 11q13.2, 7p11.2, 3q26.33, and 17q12, which harbored CCND1, EGFR, SOX2, and ERBB2, respectively. Analysis of survival data and RNAi screening data suggested that GRB7, located on 17q12, was a driver gene in ESCC. In ESCC cell lines harboring 17q12 amplification, knockdown of GRB7 reduced the proliferation, migration, and invasion capacities of cells. Moreover, siRNA targeting GRB7 had a synergistic inhibitory effect when combined with trastuzumab, an anti-ERBB2 antibody. Survival analysis of the independent cohort also showed that high GRB7 expression was associated with poor prognosis in ESCC.
Our integrative analysis provided important insights into ESCC pathogenesis. We identified GRB7 as a novel ESCC driver gene and potential new therapeutic target.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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 si
GAB2
-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 si
GAB2
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.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
