ARID1A expression in early stage colorectal adenocarcinoma: an exploration of its prognostic significance

The potential of EZH2 expression to facilitate treatment choice in stage II colorectal adenocarcinoma

BACKGROUND

The current selection criteria of patients with stage II colorectal carcinoma (CRC) suitable for adjuvant therapy are not satisfactory. Enhancer of zeste homolog 2 (EZH2) has been demonstrated to be over-expressed in CRC. However, data regarding the role of EZH2 in CRC survival remains controversial, and little is known about it in stage II CRC. Thus, we conducted this study to investigate the clinical significance of EZH2 expression in stage II CRC.

METHODS

Cases with stage II CRC resected between 2015 and 2018 were retrospectively reviewed. EZH2 expression was analyzed by immunohistochemistry using tissue microarrays. The relationship between EZH2 expression and clinicopathological variables was analyzed. Survival curves were estimated by the Kaplan-Meier approach.

RESULTS

We found high EZH2 expression in 134 of 221 analyzable stage II tumors (60.63%). No significant associations were observed between EZH2 expression and common clinicopathological factors. Survival analyses showed that cases receiving surgery alone had inferior overall survival (OS) than those receiving surgery and chemotherapy (P=0.0075) in stage II CRC with high EZH2 expression, however, metastasis-free survival (MFS) was similar between these two subgroups. Treatment choice had no impact on the survival of stage II CRC with low EZH2 expression.

CONCLUSION

The OS of stage II CRC with high EZH2 expression improved more strikingly with surgery and adjuvant chemotherapy than with surgery alone, which suggests the potential of EZH2 expression as a biomarker to help identify a subgroup of early-stage CRC benefiting from surgery and adjuvant chemotherapy. More large-scale studies are warranted to corroborate this finding and to further evaluate the predictive nature of EZH2.

Therapeutic Role of Synthetic Lethality in ARID1A-Deficient Malignancies

AT-rich interaction domain 1A (ARID1A), a mammalian switch/sucrose nonfermenting complex subunit, modulates several cellular processes by regulating chromatin accessibility. It is encoded by ARID1A, an immunosuppressive gene frequently disrupted in a many tumors, affecting the proliferation, migration, and invasion of cancer cells. Targeting molecular pathways and epigenetic regulation associated with ARID1A loss, such as inhibiting the PI3K/AKT pathway or modulating Wnt/β-catenin signaling, may help suppress tumor growth and progression. Developing epigenetic drugs like histone deacetylase or DNA methyltransferase inhibitors could restore normal chromatin structure and function in cells with ARID1A loss. As ARID1A deficiency correlates with enhanced tumor mutability, microsatellite instability, high tumor mutation burden, increased programmed death-ligand 1 expression, and T-lymphocyte infiltration, ARID1A-deficient cells can be a potential therapeutic target for immune checkpoint inhibitors that warrants further exploration. In this review, we discuss the role of ARID1A in carcinogenesis, its crosstalk with other signaling pathways, and strategies to make ARID1A-deficient cells a potential therapeutic target for patients with cancer.

ARID1A in cancer: Friend or foe?

ARID1A belongs to a class of chromatin regulatory proteins that function by maintaining accessibility at most promoters and enhancers, thereby regulating gene expression. The high frequency of ARID1A alterations in human cancers has highlighted its significance in tumorigenesis. The precise role of ARID1A in cancer is highly variable since ARID1A alterations can have a tumor suppressive or oncogenic role, depending on the tumor type and context. ARID1A is mutated in about 10% of all tumor types including endometrial, bladder, gastric, liver, biliopancreatic cancer, some ovarian cancer subtypes, and the extremely aggressive cancers of unknown primary. Its loss is generally associated with disease progression more often than onset. In some cancers, ARID1A loss is associated with worse prognostic features, thus supporting a major tumor suppressive role. However, some exceptions have been reported. Thus, the association of ARID1A genetic alterations with patient prognosis is controversial. However, ARID1A loss of function is considered conducive for the use of inhibitory drugs which are based on synthetic lethality mechanisms. In this review we summarize the current knowledge on the role of ARID1A as tumor suppressor or oncogene in different tumor types and discuss the strategies for treating ARID1A mutated cancers.

ARID1A downregulation promotes cell proliferation and migration of colon cancer via VIM activation and CDH1 suppression

According to our prior findings, ARID1A expression is decreased in colon cancer, which has a poor prognosis. In this study, we investigated the ARID1A-VIM/CDH1 signalling axis's role in colon cancer proliferation and migration. The differentially expressed genes in cells that might be controlled by ARID1A were discovered by a database screening for ARID1A knockout. qPCR was used to analyse ARID1A and EMT markers expression levels in colon cancer. We utilized siRNA RID1A to explore the influence of ARID1A silencing on EMT in CRC cells. The function of ARID1A in the colon was investigated utilizing the wound healing, transwell and CCK-8 WST- assays. The molecular mechanism by which ARID1A regulates VIM and CDH1 was elucidated using chip-qPCR. Numerous genes involved in EMT were dysregulated in the absence of ARID1A. VIM expression increased in cells lacking ARID1A expression and vice versa. Many COAD samples with high ARID1A mRNA expression had low VIM mRNA expression, despite the relevance. CDH1 gene was positively correlated with ARID1A. Moreover, siRNA-ARID1A-transfected cells accelerated cell migration and invasion and increased cell proliferation rate in vitro. Chip-qPCR analysis showed that ARID1A binds to the promoters of both genes and changes their expression in colon cancer. ARID1A inactivation is associated with VIM activation and CDH1 suppression, which might serve as crucial molecules influencing COAD prognosis, accelerate tumour progression, and shorten patients' survival time, and promote metastases of COAD. Thus, depletion of ARID1A can be therapeutically exploited by targeting downstream effects to improve cancer treatment-related outcomes.

Selective vulnerability of ARID1A deficient colon cancer cells to combined radiation and ATR-inhibitor therapy

ARID1A is frequently mutated in colorectal cancer (CRC) cells. Loss of ARID1A function compromises DNA damage repair and increases the reliance of tumor cells on ATR-dependent DNA repair pathways. Here, we investigated the effect of ionizing radiation (IR), in combination with ATR inhibitors (ATRi) in CRC cell lines with proficient and deficient ARID1A. The concept of selective vulnerability of ARID1A deficient CRC cells to ATRi was further tested in an ex vivo system by using the ATP-tumor chemosensitivity assay (ATP-TCA) in cells from untreated CRC patients, with and without ARID1A expression. We found selective sensitization upon ATRi treatment as well as after combined treatment with IR (P<0.001), especially in ARID1A deficient CRC cells (P <0.01). Knock-down of ARID1B further increased the selective radiosensitivity effect of ATRi in ARID1A negative cells (P<0.01). Mechanistically, ATRi abrogates the G2 checkpoint (P<0.01) and homologous recombination repair (P<0.01) in ARID1A deficient cells. Most importantly, ex-vivo experiments showed that ATRi had the highest radiosensitizing effect in ARID1A negative cells from CRC patients. Collectively, our results generate pre-clinical and clinical mechanistic rationale for assessing ARID1A defects as a biomarker for ATR inhibitor response as a single agent, or in a synthetic lethal approach in combination with IR.

Roles of ARID1A variations in colorectal cancer: a collaborative review

Colorectal cancer (CRC), a common malignancy, is one of the leading cause of cancer death in adults. AT-rich interaction domain 1A (ARID1A), a critical portion of the SWItch/sucrose non-fermentation (SWI/SNF) chromatin remodeling complexes, shows one of the most frequent mutant genes across different human cancer types. Deleterious variations of ARID1A has been recognized to be correlated the tumorigenesis and the poor prognosis of CRC. Here, we summarize recent advances in the clinical implications and molecular pathogenesis of ARID1A variations in CRC. According to independent data of 23 included studies, ARID1A is mutated in 3.6–66.7%. Consistently, all of the 23 relevant studies report that ARID1A functions as a specific tumor suppressor in CRC. Clinically, ARID1A variation status serves as a biomarker for survival prognosis and various therapies for CRC. Mechanistically, the pathophysiologic impacts of ARID1A variations on CRC may be associated with the co-occurrence variations of other genes (i.e., TP53, KRAS, APC, FBXW7, and PIK3CA) and the regulation of several signaling pathways being affected (i.e., WNT signaling, Akt signaling, and MEK/ERK pathway), leading to cell cycle arrest, chromatin remodeling, chromosome organization, and DNA hypermethylation of the cancer cells. The present review highlights ARID1A serving as a potent tumor suppressor and an important prognostic factor in CRC. ARID1A variations hint towards a promising tool for diagnostic tumor profiling and individualized therapeutic targets for CRC in the future.

Downregulated ARID1A by miR-185 Is Associated With Poor Prognosis and Adverse Outcomes in Colon Adenocarcinoma

AT-rich interaction domain 1A (ARID1A) is a tumor suppressor gene that mutates in several cancer types, including breast cancer, ovarian cancer, and colorectal cancer (CRC). In colon adenocarcinoma (COAD), the low expression of ARID1A was reported but the molecular reason is unclear. We noticed that ARID1A low expression was associated with increased levels of miR-185 in the COAD. Therefore, this study aims to explore ncRNA-dependent mechanism that regulates ARID1A expression in COAD regarding miR-185. The expression of ARID1A was tested in COAD cell line under the effect of miR-185 mimics compared with inhibitor. The molecular features associated with loss of ARID1A and its association with tumor prognosis were analyzed using multi-platform data from The Cancer Genome Atlas (TCGA), and gene set enrichment analysis (GSEA) to identify potential signaling pathways associated with ARID1A alterations in colon cancer. Kaplan-Meier survival curve showed that a low level of ARID1A was closely related to low survival rate in patients with COAD. Results showed that inhibiting miR-185 expression in the COAD cell line significantly restored the expression of ARID1A. Further, the increased expression of ARID1A significantly improved the prolonged overall survival of COAD. We noticed that there is a possible relationship between ARID1A high expression and tumor microenvironment infiltrating immune cells. Furthermore, the increase of ARID1A in tumor cells enhanced the response of inflammatory chemokines. In conclusion, this study demonstrates that ARID1A is a direct target of miR-185 in COAD that regulates the immune modulations in the microenvironment of COAD.

Role and potential clinical utility of ARID1A in gastrointestinal malignancy

ARID1A (AT-rich interactive domain 1A) is a newly discovered tumor suppressor gene, and its encoded product is an important component of the SWI/SNF chromatin remodeling complex. ARID1A plays an important role in cell proliferation, invasion and metastasis, apoptosis, cell cycle regulation, epithelial mesenchymal transition, and the regulation of other of biological behaviors. Recently, ARID1A mutations have been increasingly reported in esophageal adenocarcinoma, gastric cancer, colorectal cancer, hepatocellular carcinoma, cholangiocarcinoma, pancreatic cancer, and other malignant tumors of the digestive system. This article reviews the relationship between ARID1A mutation and the molecular mechanisms of carcinogenesis, including microsatellite instability and the PI3K/ATK signaling pathway, and relates these mechanisms to the prognostic assessment of digestive malignancy. Further, this review describes the potential for molecular pathologic epidemiology (MPE) to provide new insights into environment-tumor-host interactions.

Molecular screening and clinicopathologic characteristics of Lynch-like syndrome in a Chinese colorectal cancer cohort

Colorectal cancers (CRC) with microsatellite instability (MSI) or mismatch repair-deficiency (dMMR), but without detectable MMR germline mutations are termed Lynch-like syndrome (LLS). We assess the clinicopathologic and molecular characteristics of LLS tumors and the proportion in LLS, which remain poorly investigated in China. We enrolled 404 CRC patients with surgery in our institution from 2014 to 2018. LLS tumors were detected by a molecular stratification based on MMR protein expression, MLH1 methylation and MMR gene mutation. LLS tumors were profiled for germline mutations in 425 cancer-relevant genes. Among 42 MMR-deficient tumors, 7 (16.7%) were attributable to MLH1 methylation and 7 (16.7%) to germline mutations, leaving 28 LLS cases (66.6%). LLS tumors were diagnosed at a mean age of 60.7 years, had an almost equivalent ratio among rectum, left colon and right colon, and had high rates of lymph node metastases (50%, 4/28 N2). Most MMR gene mutations (88.2%, 15/17) in LLS tumors were variants of unknown significance (VUS). Two novel frameshift mutations were detected in ATM and ARID1A, which are emerging as candidate responsible genes for LLS. In this study, 28 (66.6%) MMRd tumors were classified as LLS, which were significantly higher than reports of western countries. LLS tumors were more likely to carry lymph node metastases. However, it's hard to differentiated LLS tumors from LS through family history, tumor location, histological type of tumors, immunohistochemistry (IHC) for MMR proteins and MSI analysis.

Altered ARID1A expression in colorectal cancer

Background

ARID1A has been described as a tumor suppressor gene, participating in chromatin re-modeling, epithelial-mesenchymal-transition and many other cellular and molecular processes. It has been cited as a contribute in tumorigenesis. The role of ARID1A in CRC is not yet defined.

Aim

To investigate the role of ARID1A methylation and CNV in its expression in CRC cell lines and to examine the relationship between ARID1A status with survival and clinicopathologic characteristics in patients with CRC.

Methods

We used RT-PCR to determine both CNV and expression of ARID1A from six CRC cell lines. We used MSP to evaluate methylation of ARID1A. IHC was used to assess ARID1A protein expression. We also evaluated MSI and EMAST status in 18 paired CRC and adjacent normal tissues. 5AzadC was used to assess effect of DNA demethylation on ARID1A expression. Statistical analysis was performed to establish correlations between ARID1A expression and other parameters.

Results

Among the 18 CRC tumors studied, 7 (38.8%) and 5 tumors (27.7%) showed no or low ARID1A expression, respectively. We observed no significant difference in ARID1A expression for overall patient survival, and no difference between clinicopathological parameters including MSI and EMAST. However, lymphatic invasion was more pronounced in the low/no ARID1A expression group when compared to moderate and high expression group (33% VS. 16.6% respectively. ARID1A promoter methylation was observed in 4/6 (66%) cell lines and correlated with ARID1A mRNA expression level ranging from very low in SW48, to more pronounced in HCT116 and HT-29/219. Treatment with the methyltransferase inhibitor 5-Azacytidine (5-aza) resulted in a 25.4-fold and 6.1-fold increase in ARID1A mRNA expression in SW48 and SW742 cells, respectively, while there was no change in SW480 and LS180 cells. No ARID1A CNV was observed in the CRC cell lines.

Conclusion

ARID1A expression is downregulated in CRC tissues which correlates with it being a tumor suppressor protein. This finding confirms ARID1A loss of expression in CRC development. Our in-vitro results suggest high methylation status associates with reduced ARID1A expression and contributes to CRC tumorigenesis. However, there was no significant association between ARID1A loss of expression and clinicopathological characteristics. Future in-vivo analysis is warranted to further establish ARID1A role in colorectal neoplastic transformation.

Switch/sucrose nonfermenting nucleosome complex-deficient colorectal carcinomas have distinct clinicopathologic features

The switch/sucrose nonfermenting (SWI/SNF) nucleosome complex consists of several proteins that are involved in cellular proliferation and tumor suppression. The aim of this study was to correlate immunohistochemical expression of four SWI/SNF complex subunits, SMARCA2, SMARCB1, SMARCA4, and ARID1A, with clinicopathologic and molecular features and patient survival in 338 patients with colorectal adenocarcinoma using a tissue microarray approach. Twenty-three (7%) colorectal adenocarcinomas demonstrated deficient SWI/SNF expression: 7 had SMARCA2 deficiency, 12 had ARID1A deficiency, and 4 had both SMARCA2 and ARID1A deficiency. No cases were SMARCB1 or SMARCA4 deficient. Twelve (52%) SWI/SNF complex-deficient tumors demonstrated mismatch repair (MMR) deficiency (p = 0.02), 6 (26%) showed medullary differentiation (p = 0.001), and 9 were negative for CDX2 expression (p < 0.001). Among the MMR-deficient SWI/SNF complex-deficient tumors, 8 were sporadic MLH1 deficient, and 4 were seen in patients with Lynch syndrome. Compared with tumors with ARID1A deficiency alone, SMARCA2-deficient tumors were less likely to exhibit MMR deficiency (27% vs. 75%, p = 0.04), medullary differentiation (0% vs. 50%, p = 0.01), and mucinous differentiation (0% vs. 42%, p = 0.04). Conventional gland-forming histology was more often identified in SMARCA2-deficient tumors (11/11, 100%) than in tumors with ARID1A deficiency alone (4/12, 33%) (p = 0.001). There was no difference in KRAS mutation, BRAF mutation, stage, disease-specific survival, or disease-free survival for patients stratified by SWI/SNF expression (all with p > 0.05). In conclusion, SMARCA2-deficient and ARID1A-deficient colorectal carcinomas had distinctly different clinicopathologic features, with ARID1A-deficient tumors exhibiting medullary and mucinous differentiation and MMR deficiency and SMARCA2-deficient tumors demonstrating conventional gland-forming histologic growth with less frequent MMR deficiency.

Associations Between Loss of ARID1A Expression and Clinicopathologic and Genetic Variables in T1 Early Colorectal Cancer

OBJECTIVES

To evaluate the relationships between adenine-thymine-rich interactive domain 1A (ARID1A) expression and the clinicopathologic features in T1 colorectal cancer (CRC) and to investigate whether the presence of ARID1A protein is related to genetic changes.

METHODS

We retrospectively studied 219 surgically resected T1 CRCs. ARID1A expression was assessed by immunohistochemical methods, and the correlation between ARID1A expression and clinicopathologic features was evaluated. The relationship between ARID1A expression and 409 cancer-related gene mutations was also evaluated using next-generation sequencing (NGS).

RESULTS

Immunohistochemical staining indicated negative ARID1A expression in 4.6%. Loss of ARID1A expression was significantly associated with younger age, lymphatic invasion, and lymph node metastasis (LNM). NGS showed that PKHD1, RNF213, and MSH6 mutations were more frequent in ARID1A-negative tumors, whereas KRAS mutations were more common in ARID1A-positive tumors.

CONCLUSIONS

In T1 CRC, negative ARID1A expression was correlated with early onset, lymphatic invasion, and LNM. Mutations in some cancer-related genes were possibly related with ARID1A expression.

Alteration of Epigenetic Modifiers in Pancreatic Cancer and Its Clinical Implication

The incidence of pancreatic cancer has considerably increased in the past decade. Pancreatic cancer has the worst prognosis among the cancers of the digestive tract because the pancreas is located in the posterior abdominal cavity, and most patients do not show clinical symptoms for early detection. Approximately 55% of all patients are diagnosed with pancreatic cancer only after the tumors metastasize. Therefore, identifying useful biomarkers for early diagnosis and screening high-risk groups are important to improve pancreatic cancer therapy. Recent emerging evidence has suggested that genetic and epigenetic alterations play a crucial role in the molecular aspects of pancreatic tumorigenesis. Here, we summarize recent progress in our understanding of the epigenetic alterations in pancreatic cancer and propose potential synthetic lethal strategies to target these genetic defects to treat this deadly disease.

Keratin 8 is a potential self-antigen in the coronary artery disease immunopeptidome: A translational approach

Background

Inflammation is an important risk factor in atherosclerosis, the underlying cause of coronary artery disease (CAD). Unresolved inflammation may result in maladaptive immune responses and lead to immune reactivity to self-antigens. We hypothesized that inflammation in CAD patients would manifest in immune reactivity to self-antigens detectable in soluble HLA-I/peptide complexes in the plasma.

Methods

Soluble HLA-I/peptide complexes were immuno-precipitated from plasma of male acute coronary syndrome (ACS) patients or age-matched controls and eluted peptides were subjected to mass spectrometry to generate the immunopeptidome. Self-peptides were ranked according to frequency and signal intensity, then mouse homologs of selected peptides were used to test immunologic recall in spleens of male apoE-/- mice fed either normal chow or high fat diet. The peptide detected with highest frequency in patient plasma samples and provoked T cell responses in mouse studies was selected for use as a self-antigen to stimulate CAD patient peripheral blood mononuclear cells (PBMCs).

Results

The immunopeptidome profile identified self-peptides unique to the CAD patients. The mouse homologs tested showed immune responses in apoE-/- mice. Keratin 8 was selected for further study in patient PBMCs which elicited T Effector cell responses in CAD patients compared to controls, associated with reduced PD-1 mRNA expression.

Conclusion

An immunopeptidomic strategy to search for self-antigens potentially involved in CAD identified Keratin 8. Self-reactive immune response to Keratin 8 may be an important factor in the inflammatory response in CAD.

Exportin-T promotes tumor proliferation and invasion in hepatocellular carcinoma

Exportin-T (XPOT) belongs to the RAN-GTPase exportin family that mediates export of tRNA from the nucleus to the cytoplasm. Up-regulation of XPOT indicates poor prognosis in breast cancer patients. However, the correlation between XPOT and hepatocellular carcinoma (HCC) remains unclear. Here, we found that high expression of XPOT in HCC indicated worse prognosis via bioinformatics analysis. Consistently, immunohistochemical staining of 95 pairs of tumors and adjacent normal liver tissues (ANLT) also showed up-regulation of XPOT. Small interfering (si) RNA transfection was used to down-regulate XPOT in HepG2 and 7721 cell lines. Cell Counting Kit-8 (CCK8) assays were performed to analyze cell proliferation. Cell migration and invasion were measured by scratch wound healing assays and migration assays. Subcutaneous xenograft models were using to explore the role of XPOT in tumor formation in vivo. Down-regulation of XPOT significantly inhibited tumor proliferation and invasion in vitro and vivo. Gene set enrichment analysis (GSEA) results indicated that XPOT may affect tumor progression through cell cycle and ubiquitin-mediated proteolysis. Furthermore, knockdown of XPOT caused a block in G0/G1 phase as evidenced by down-regulation of cyclin-dependent kinase 1 (CDK1), cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), CyclinA1 (CCNA1), CyclinB1 (CCNB1), CyclinB2 (CCNB2), and CyclinE2 (CCNE2) in HCC cells. In conclusion, our findings indicate that XPOT could serve as a novel biomarker for prognoses and a potential therapeutic target for patients with HCC.

Prognostic significance of tumor genotypes and CD8+ infiltrates in stage I-III colorectal cancer

Background

We explored the clinical significance of tumor genotypes and immunophenotypes in non-metastatic colorectal cancer (CRC).

Methods

In primary tumors (paraffin blocks) from 412 CRC patients treated with adjuvant chemotherapy, we examined pathogenic mutations (panel NGS; 347 informative); mismatch repair (MMR) immunophenotype (360 informative); and CD8+ lymphocyte density (high – low; 412 informative). The primary outcome measure was disease-free survival (DFS).

Results

We evaluated 1713 pathogenic mutations (median: 3 per tumor; range 0-49); 118/412 (28.6%) tumors exhibited high CD8+ density; and, 40/360 (11.1%) were MMR-deficient. Compared to MMR-proficient, MMR-deficient tumors exhibited higher CD8+ density (chi-square, p<0.001) and higher pathogenic mutation numbers (p=0.003). High CD8+ density was an independent favorable prognosticator (HR=0.49, 95%CI 0.29-0.84, Wald's p=0.010). Pathogenic BRCA1 and ARID1A mutations were inversely associated with each other (p<0.001), were not associated with MMR-deficiency or CD8+ density, but both independently predicted for unfavorable DFS (HR=1.98, 95%CI 1.12-3.48, p=0.018 and HR=1.99, 95%CI 1.11-3.54, p=0.020, respectively).

Conclusion

In non-metastatic CRC, high CD8+ lymphocyte density confers a favorable prognosis and may be developed as a single marker in routine diagnostics. The unfavorable prognostic effect of pathogenic BRCA1 and ARID1A mutations is a novel observation that, if further validated, may improve treatment selection.

Unique characteristics of ARID1A mutation and protein level in gastric and colorectal cancer: A meta-analysis

BACKGROUND/AIM

Recently, AT-rich interactive domain-containing 1A protein (ARID1A) has been identified as a novel tumor suppressor gene in gastric cancer (GC) and colorectal cancer (CRC). However, the clinicopathologic value of ARID1A mutation or protein level in GC and CRC patients is controversial. Hence, we conducted a meta-analysis on the relationship between ARID1A aberrations and clinicopathologic parameters in GC and CRC.

MATERIALS AND METHODS

Relevant published studies were selected from PubMed and EMBASE. The effect sizes of ARID1A mutation or level on the patient's clinicopathologic parameters were calculated by prevalence rate or odds ratio (OR) or hazard ratio (HR), respectively. The effect sizes were combined using a random-effects model.

RESULTS

The frequency of ARID1A mutation and loss of ARID1A protein expression in GC patients was 17% and 27%, respectively. The loss of ARID1A protein expression of GC patients was significantly associated with advanced tumor depth (OR = 1.8, P = 0.004), lymph node metastasis (OR = 1.4, P = 0.001), and unfavorable adjusted overall survival (HR = 1.5, P < 0.001). ARID1A mutation of GC was significantly associated with microsatellite instability (MSI) (OR = 24.5, P < 0.001) and EBV infection (OR = 2.6, P = 0.001). The frequency of ARID1A mutation and ARID1A protein expression loss in CRC patients was approximately 12-13%. Interestingly, the loss of ARID1A protein expression in CRC patients was significantly associated with poorly differentiated grade (OR = 4.0, P < 0.001) and advanced tumor depth (OR = 1.8, P = 0.012).

CONCLUSION

Our meta-analysis revealed that ARID1A alterations may be involved in the carcinogenesis of GC by EBV infection and MSI. The loss of ARID1A protein expression may be a marker of poor prognosis in GC and CRC patients.