Microsatellite instability status and its clinical significance in patients with colorectal cancer: a multicenter database study

149 Background: Microsatellite instability (MSI) plays a crucial role as a cancer immunotherapy and prognosis biomarker, making accurate MSI detection essential. However, currently, there is still a lack of available data on the impact of neoadjuvant therapy on MSI status, as well as validated data on standardized methods for MSI testing in small biopsy samples. The study aimed to investigate the concordance of MSI status between paired biopsy and surgical samples, as well as the impact of neoadjuvant therapy on MSI status using a novel MSI next-generation sequencing (MSI-NGS) detection panel. Methods: A total of 137 colorectal cancer (CRC) patients were enrolled for this study, of whom 116 with paired biopsy and surgical samples were analyzed. A custom MSI-NGS panel was employed and its performance was compared to MSI polymerase chain reaction (MSI-PCR), which served as the gold standard. Results: Out of the 116 cases, 112 patients showed consistent MSI status between biopsy and surgical samples, with an overall accuracy of 97% regardless of the detection method used. In the cases with MSI discrepancy (6 cases), 83% (5/6) of the patients showed a transition from MSS to MSI-H from biopsy to surgery. Interestingly, all eight patients who received neoadjuvant chemotherapy maintained an unchanged MSI status. However, in one patient who received adjuvant treatment and underwent a repeat biopsy after surgery, the MSI status exhibited alterations. Further analysis of clonal evolution revealed that this heterogeneity stemmed from the disappearance of the original clones and the emergence of new clones. Additionally, the NGS panel exhibited strong concordance with MSI-PCR and high accuracy, sensitivity and specificity with an AUC of 0.942 after rigorous validation. Conclusions: The study revealed a high concordance in MSI status between paired biopsy and surgical samples by employing a custom MSI-NGS panel for MSI status detection, providing reliable basis for further research in this field. Moreover, neoadjuvant chemotherapy seemed to have no impact on MSI status in our study, whereas postoperative adjuvant chemotherapy may influence changes in MSI status, highlighting the necessity of reevaluating MSI status after surgery. The findings also underscore the potential of NGS-based MSI detection as a valuable tool for clinical decision-making.

607 Background: Preoperative serum systemic inflammatory response (SIR) has been reported in patients with various cancers including colorectal cancer (CRC) as predictive biomarker of early recurrence. Molecular phenotypes of CRC including microsatellite instability (MSI) status and tumor infiltrating lymphocytes (TILs) have also known to be associated with recurrence in curative CRC patients. We comprehensively evaluated SIR status, MSI status and TILs in curative CRC patients and investigated which can be promising as high risk markers of recurrence in these patients. Methods: This retrospective study enrolled 157 CRC patients with stage I-III undergoing curative operation for whom preoperative neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and CRP were available as indicators of SIR status. For analysis of molecular phenotypes, we evaluated TILs by counting the number of intra-tumor Foxp3 and CD8 positive T cells by IHC analysis. Next, MSI status was determined in using 5 mononucleotide repeat microsatellite markers. Finally, we investigated the impact of SIR status, TILs and MSI status on the recurrence of these patients. Results: This study included a total of 90 males and 67 females, with an average age of 66.9 years. Twenty-nine patients (18.4%) developed recurrence. Kaplan-Meier analysis using SIR indicators revealed that patients with high CRP, NLR and PLR levels were significantly poorer disease free survival (DFS) than those with low levels. Low infiltrating CD8-positive T cells were significantly predictive factors for poor DFS, but there was no correlation between MSI status and recurrence, In univariate analysis, low infiltrating CD8-positive T cells, high CEA, CRP, NLR and PLR levels in serum were significantly predictive factors for poor DFS, respectively. Multivariate analysis showed that low infiltrating CD8-positive T cells and high serum CRP levels were independent predictive markers for recurrence in curative CRC patients. Conclusions: We demonstrated that evaluation of both CRP levels in preoperative serum and tumor infiltrating CD8 lymphocytes in CRC tissues are useful to predict the curative CRC patients with early relapse.

Introduction: The MSI status of a tumor is often a marker of deoxyribonucleic acid (DNA) mismatch repair deficiency. Recent clinical trials have shown MSI-High (MSI-H) tumors are more likely to respond to checkpoint inhibitor immunotherapy. The United States Food and Drug Administration recently granted approval for a checkpoint inhibitor in metastatic solid tumor that demonstrates high microsatellite instability. Here we show the accuracy of determining the MSI status of colorectal cancers (CRC) using either TruSight™ Tumor 170 (TST170), a NGS-based 170 gene panel for solid tumor profiling, or whole exome sequencing (WES). Further, we report the accuracy of identifying the MSI status through sequencing of tumor-only samples without the subject-matched normal DNA. Experimental Method: The MSI status of 52 CRC tumors (51 formalin-fixed, paraffin embedded and 1 fresh-frozen sample) were evaluated using a microsatellite instability (MSI) assay (Promega), which is a detection method that uses capillary electrophoresis to analyze PCR-products. For comparison to WES, the tumors and subject-matched normal DNA libraries were prepared and enriched using TruSight™ Oncology reagents (Illumina). Targeted NGS libraries were prepared and enriched for the TST170-gene panel using the TST170 library kit (Illumina). NGS libraries were sequenced with the HiSeq™ 2000, HiSeq™ 2500, or NextSeq™ 550 instruments (Illumina). MSI scores of the 52 tumors were calculated through a novel internally developed bioinformatics algorithm. Data Summary: From the 52 subjects assessed through Promega's MSI detection kit, 28 and 24 were found to be MSI-H and microsatellite stable (MSS), respectively. These data were used as the benchmark for the MSI status of these subjects. Both the NGS-based tumor-normal data from WES and TST170 achieved a 100% concordance with PCR-based MSI detection. In addition, when only the sequencing data of the tumor samples were used without the subject-matched normal DNA, the Illumina MSI algorithm could identify the MSI status of the 52 subjects with 98% concordance with Promega's MSI detection kit. Conclusion: Collectively, this data indicates that NGS can be utilized for determining tumor MSI status using WES or the TST170 panel. In addition, a bioinformatics algorithm was developed that successfully categorized tumors according to their MSI status without requiring subject-matched normal DNA sequence data. For Research Use Only. Not for use in diagnostic procedures. Citation Format: Alex So, Shile Zhang, Shannon Kaplan, Joyee Yao, Phillip Le, Christine Glidewell-Kenney, Kristina Kruglyak, Jenny Jie Chen, Ali Kuraishy, Ina Deras, Karen Gutekunst. Determining microsatellite instability (MSI) status of colorectal cancers through next-generation sequencing (NGS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3414.

Background: MSI status, along with PD-L1 expression and tumor mutational burden (TMB), is an important predictive biomarker for immune checkpoint inhibitors. Recent studies demonstrated that next-generation sequencing (NGS)-based MSI assays can simultaneously detect MSI status and variants in other target genes. We developed and validated an NGS-based MSI assay that utilizes data from a 49 gene panel used for solid tumor profiling. Here we report the concordance of this NGS-MSI assay with 2 commonly used PCR fragment-based methods for MSI status. We also evaluated the relationship between NGS-MSI status and TMB as assessed with the 49-gene solid-tumor profiling assay. Method: This study used de-identified, formalin-fixed, paraffin embedded tumor tissue and adjacent normal tissue from 55 patients with colorectal cancer. All specimens were tested with a hybrid capture-based 49-gene NGS assay on the Illumina NextSeq500 platform. Components of the MSIsensor software v0.2 and a Fisher’s Exact test were used to discriminate the repeat distributions between the tumor and normal specimens on the following MSI markers: BAT25, BAT26, NR21, NR24, and NR27. Specimens demonstrating instability in 2 or more the 5 markers were considered MSI positive (MSI-H), and others were considered MSI negative (MSI-L/MSS).NGS-MSI results were compared to those of the Bethesda NCI panel (BAT25, BAT-26, D5S346, D2S123 and D17S250) (55 patients) and the Promega MSI test (BAT25, BAT26, NR21, NR24 and Mono27) (52 patients). TMB was compared between NGS-MSI-positive and NGS-MSI-negative specimens. Results: The NGS-MSI assay showed strong concordance with both the Bethesda NCI panel and the Promega MSI test. Concordance between the NGS-MSI and Bethesda-MSI test was 97% (53/55): 26 specimens were concordant for MSI positive and 27 were concordant for MSI negative, while 2 were MSI negative by NGS-MSI but MSI-H by Bethesda-MSI. Concordance between the NGS-MSI and Promega-MSI tests was 98% (51/52): 25 specimens were MSI positive/MSI-H and 26 were MSI negative/MSS or MSI-l. The discordant specimen was MSI-negative by NGS-MSI and MSI-H by Promega-MSI. The mean TMB was higher in MSI-positive (11.3 mutations/specimen) than in NGS-MSI-negative specimens (2.5 mutations/specimen). The mutations and its relationship with MSI status in 4 DNA mismatch repair genes (MLH1, PMS2, MSH2 and MSH6) were under analysis. Conclusion: The NGS-based MSI assay, performed as part of a 49-gene NGS tumor profiling test, demonstrated strong concordance with the Bethesda and Promega MSI tests. As expected, MSI-positive tumor specimens had higher TMB than did MSI-negative samples. Citation Format: Kevin Z. Qu, Suzzette Arnal, Sirisha Sunkara, Mohammad R. Sheikholeslami, Zhong J. Zhang, Felicitas L. Lacbawan, Charles Ma, Sugganth Daniel. Assessment of microsatellite instability (MSI) status in colorectal cancer tissue using a next-generation sequencing-based tumor profiling assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4026.

Stratification of microsatellite instability (MSI) status in patients with colorectal cancer (CRC) improves clinical decision-making for cancer treatment. The present study aimed to develop a radiomics nomogram to predict the pre-treatment MSI status in patients with CRC. A total of 762 patients with CRC confirmed by surgical pathology and MSI status determined with polymerase chain reaction (PCR) method were retrospectively recruited between January 2013 and May 2019. Radiomics features were extracted from routine pre-treatment abdominal pelvic computed tomography (CT) scans acquired as part of the patients' clinical care. A radiomics nomogram was constructed using multivariate logistic regression. The performance of the nomogram was evaluated using discrimination, calibration, and decision curves. The radiomics nomogram incorporating radiomics signatures, tumor location, patient age, high-density lipoprotein expression, and platelet counts showed good discrimination between patients with non-MSI-H and MSI-H, with an area under the curve (AUC) of 0.74 [95% CI, 0.68-0.80] in the training cohort and 0.77 [95% CI, 0.68-0.85] in the validation cohort. Favorable clinical application was observed using decision curve analysis. The addition of pathological characteristics to the nomogram failed to show incremental prognostic value. We developed a radiomics nomogram incorporating radiomics signatures and clinical indicators, which could potentially be used to facilitate the individualized prediction of MSI status in patients with CRC. • There is an unmet need to non-invasively determine MSI status prior to treatment. However, the traditional radiological evaluation of CT is limited for evaluating MSI status. • Our non-invasive CT imaging-based radiomics method could efficiently distinguish patients with high MSI disease from those with low MSI disease. • Our radiomics approach demonstrated promising diagnostic efficiency for MSI status, similar to the commonly used IHC method.

SummaryBackgroundResponse to immunotherapy in gastric cancer is associated with microsatellite instability (or mismatch repair deficiency) and Epstein-Barr virus (EBV) positivity. We therefore aimed to develop and validate deep learning-based classifiers to detect microsatellite instability and EBV status from routine histology slides.MethodsIn this retrospective, multicentre study, we collected tissue samples from ten cohorts of patients with gastric cancer from seven countries (South Korea, Switzerland, Japan, Italy, Germany, the UK and the USA). We trained a deep learning-based classifier to detect microsatellite instability and EBV positivity from digitised, haematoxylin and eosin stained resection slides without annotating tumour containing regions. The performance of the classifier was assessed by within-cohort cross-validation in all ten cohorts and by external validation, for which we split the cohorts into a five-cohort training dataset and a five-cohort test dataset. We measured the area under the receiver operating curve (AUROC) for detection of microsatellite instability and EBV status. Microsatellite instability and EBV status were determined to be detectable if the lower bound of the 95% CI for the AUROC was above 0·5.FindingsAcross the ten cohorts, our analysis included 2823 patients with known microsatellite instability status and 2685 patients with known EBV status. In the within-cohort cross-validation, the deep learning-based classifier could detect microsatellite instability status in nine of ten cohorts, with AUROCs ranging from 0·597 (95% CI 0·522–0·737) to 0·836 (0·795–0·880) and EBV status in five of eight cohorts, with AUROCs ranging from 0·819 (0·752–0·841) to 0·897 (0·513–0·966). Training a classifier on the pooled training dataset and testing it on the five remaining cohorts resulted in high classification performance with AUROCs ranging from 0·723 (95% CI 0·676–0·794) to 0·863 (0·747–0·969) for detection of microsatellite instability and from 0·672 (0·403–0·989) to 0·859 (0·823–0·919) for detection of EBV status.InterpretationClassifiers became increasingly robust when trained on pooled cohorts. After prospective validation, this deep learning-based tissue classification system could be used as an inexpensive predictive biomarker for immunotherapy in gastric cancer.FundingGerman Cancer Aid and German Federal Ministry of Health.

BackgroundDespite their pivotal roles in colorectal carcinogenesis, the interrelationship and prognostic significance of beta-catenin alterations and microsatellite instability (MSI) in colorectal cancer (CRC) needs to be further clarified. In this paper, we studied the associations between beta-catenin overexpression and MSI status with survival from CRC, and with expression of p21, p27, cyclin D1 and p53, in a large, prospective cohort study.MethodsImmunohistochemical MSI-screening status and expression of p21, p27 and p53 was assessed in tissue microarrays with tumours from 557 cases of incident CRC in the Malmö Diet and Cancer Study. Chi Square and Spearman’s correlation tests were used to explore the associations between beta-catenin expression, MSI status, clinicopathological characteristics and investigative parameters. Kaplan-Meier analysis and Cox proportional hazards modelling were used to assess the relationship between beta-catenin overexpression, MSI status and cancer specific survival (CSS).ResultsPositive MSI screening status was significantly associated with older age, female sex, proximal tumour location, non-metastatic disease, and poor differentiation, and inversely associated with beta-catenin overexpression. Beta-catenin overexpression was significantly associated with distal tumour location, low T-stage and well-differentiated tumours. Patients with MSI tumours had a significantly prolonged CSS in the whole cohort, and in stage III-IV disease, also in multivariable analysis, but not in stage I-II disease. Beta-catenin overexpression was associated with a favourable prognosis in the full cohort and in patients with stage III-IV disease. Neither MSI nor beta-catenin status were predictive for response to adjuvant chemotherapy in curatively treated stage III patients. P53 and p27 expression was positively associated with beta-catenin overexpression and inversely associated with MSI. Cyclin D1 expression was positively associated with MSI and beta-catenin overexpression, and p21 expression was positively associated with MSI but not beta-catenin overexpression.ConclusionsFindings from this large, prospective cohort study demonstrate that MSI screening status in colorectal cancer is an independent prognostic factor, but not in localized disease, and does not predict response to adjuvant chemotherapy. Beta-catenin overexpression was also associated with favourable outcome but not a treatment predictive factor. Associations of MSI and beta-catenin alterations with other investigative and clinicopathological factors were in line with the expected.Virtual slidesThe virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8778585058652609

BackgroundThis study aimed to develop and validate a computed tomography (CT)-based radiomics model to predict microsatellite instability (MSI) status in colorectal cancer patients and to identify the radiomics signature with the most robust and high performance from one of the three phases of triphasic enhanced CT.MethodsIn total, 502 colorectal cancer patients with preoperative contrast-enhanced CT images and available MSI status (441 in the training cohort and 61 in the external validation cohort) were enrolled from two centers in our retrospective study. Radiomics features of the entire primary tumor were extracted from arterial-, delayed-, and venous-phase CT images. The least absolute shrinkage and selection operator method was used to retain the features closely associated with MSI status. Radiomics, clinical, and combined Clinical Radiomics models were built to predict MSI status. Model performance was evaluated by receiver operating characteristic curve analysis.ResultsThirty-two radiomics features showed significant correlation with MSI status. Delayed-phase models showed superior predictive performance compared to arterial- or venous-phase models. Additionally, age, location, and carcinoembryonic antigen were considered useful predictors of MSI status. The Clinical Radiomics nomogram that incorporated both clinical risk factors and radiomics parameters showed excellent performance, with an AUC, accuracy, and sensitivity of 0.898, 0.837, and 0.821 in the training cohort and 0.964, 0.918, and 1.000 in the validation cohort, respectively.ConclusionsThe proposed CT-based radiomics signature has excellent performance in predicting MSI status and could potentially guide individualized therapy.

Predicting Microsatellite Instability Status in Colorectal Cancer Based on Triphasic Enhanced Computed Tomography Radiomics Signatures: A Multicenter Study

IntroductionIn Uganda, colorectal cancer (CRC) is steadily increasing according to the Kampala Cancer Registry. In the West, microsatellite instability is detected in 90% of hereditary nonpolyposis colon cancers (HNPCC) which account for 1–2% of all CRC, and 15% of sporadic CRC. Germline mutations in MLH1 and MSH2 account for 90% of HNPCC in the West, whilst the remainder of cases are due to mutations in MSH6 and PMS2. The aim of this study was to determine the microsatellite instability (MSI) status and determine the proportions of MLH1, MSH2, and MSH6 pathological mutations in Ugandan CRC patients.MethodologyThis was a cross-sectional study carried out between 1st January 2008 to 15th September 2021. Patients were recruited prospectively from 16th September 2019 to 16th September 2021, from Masaka Regional Referral Hospital, Mulago National Referral Hospital, Uganda Martyrs’ Hospital Lubaga and Mengo Hospital. From 1st January 2008 to 15th September 2019, CRC FFPE tissue blocks were obtained from the archives of the Department of Pathology, Makerere University. Data was abstracted from the medical case files for demographics, topography and stage. The histopathological subtype and grade of CRC were obtained by two consultant pathologists from the H&E slides. DNA was extracted from CRC formalin-fixed paraffin-embedded (FFPE) tissue blocks. Library preparation was completed using the Qiagen custom design panel. The custom panel represented 56 genes. The MLH-1, MSH2, MSH6, BRAF and KRAS genes were sequenced using the above library preparation and NGS sequencing. The MSI status was obtained if one of the MSI genes, MLH1, MSH2 or MSH6 was pathologically mutated. If none of the genes was pathologically mutated it was considered MSI negative, microsatellite stable (MSS). Immunohistochemistry was carried out to determine whether MLH1 and PMS2 was MMR proficient or deficient. Categorical data was summarized using frequencies and proportions corresponding to each of the three histopathological subtypes and MSI status subtypes. Continuous and categorical variables were analyzed using the chi-square and Fischer’s exact tests. A p -value ≤ 0.05 was considered statistically significant for all the analyses.ResultsOut of 127 CRC patients, the mean(SD) age of MSI cases was 55.6(16.9) years and of MSS cases was 55.4(15.5) years. The majority were MSS, 75(59.06%) followed by MSI, 52(40.9%). There were 14(11.02%) MLH-1 mutations, 30(23.62%) MSH2 mutations, and 26(20.47%) MSH6 mutations. BRAF mutational analysis showed only 5(3.9%) having pathologic missense BRAF V600 mutations. KRAS mutations consisted of only 8(6.3%) having pathologic missense KRAS mutations.ConclusionsThe high rate of MSI in Ugandan colorectal tumours was mainly associated with a lack of BRAF mutations and a high frequency of MSH2 and MSH6 MMR gene mutations. In CRC patients, identification of the causative mutation is recommended, however in a resource-limited setting, MSI testing and immunohistochemistry is more cost effective. In Ugandan CRC patients who meet at least one of the Bethesda criteria, MSI testing and immunohistochemistry may therefore be offered to obtain the MSI status of the tumour.

Clinical significance of combined tumour-infiltrating lymphocytes and microsatellite instability status in colorectal cancer: a systematic review and network meta-analysis

AT-rich interactive domain-containing protein 1A (ARID1A) is a subunit of the SWI-SNF chromatin-remodeling complex, which is considered to perform a tumor suppressor function. Somatic mutations of ARID1A were reported to be detected in about 50% of colorectal cancer (CRC), but loss of expression seems vary according to tissue type and microsatellite instability (MSI) status. So, we designed this study to identify the frequency of loss of ARID1A expression and its clinical relevance in CRC and gastric cancer (GC) of Korean patients. Immunohistochemistry for ARID1A was performed using tissue microarray blocks containing 197 CRCs and 275 SCs, and paired normal mucosa. Data on MSI status were available in 178 of 197 CRCs and 233 of 275 GCs. Clinicopathological data of the patients were collected and analyzed. We identified 12 (12/197, 6.1%) CRCs showing loss of ARID1A expression, all of which were microsatellite stable. In 178 CRCs with identified MSI status, 3 (1.7%) MSI-H and 6 (3.4%) MSI-L tumors showed normal expression of ARID1A, contrary to MSS tumors (ARID1A loss: 10/169, 5.9%). Among GCs, 8.0% (22/275) showed loss of ARID1A expression and 6.4% (15/233) were MSI-H. Tumors with loss of ARID1A expression accounted for 13.3% (2/13) of GCs with MSI-H whereas 5.0% (11/207) of GCs with MSS. However, there was no association between ARID1A expression and MSI status in both CRCs (p=0.754) and SCs (p=0.200). Expression of ARID1A in paired normal mucosal epithelial cells was normal in all patients. Clinicopathological factors were not associated with ARID1A expression in both cancers except that CRCs with loss of ARID1A expression showed less frequent lymphatic invasion than those with normal expression (25.0% vs. 69.0%, p=0.003). There was no association between ARID1A expression and 3-year disease-free survival or 5-year overall survival in both cancers. In this study population, loss of ARID1A expression was uncommon and not relevant to MSI-H tumors. Its clinical implication for the prognosis of CRC and GC patients seems to need further studies with more accumulated data. Citation Format: Soo Young Lee, Duck-Woo Kim, Hye Seung Lee, Myong Hoon Ihn, Heung-Kwon Oh, Sung-Bum Kang. ARID1A expression and its relation with microsatellite instability and clinicopathological characteristics in colorectal and gastric cancers of Korean patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4673. doi:10.1158/1538-7445.AM2014-4673

Microsatellite instability-high status enhances lymph node yield and reduces optimal dissection thresholds in colorectal cancer: A retrospective cohort analysis with β-binomial modeling.

Microsatellite instability (MSI) implies the deletion of mismatch repair genes caused by DNA methylation or gene mutation. MSI is a good predictor for efficacy of 5-fluorouracil (FU)-based chemotherapy in the treatment of colorectal cancer. Some gastric cancer studies have reported that MSI has no apparent impact on prognosis after patients receive 5-FU-based adjuvant chemotherapy. However, other studies suggest that high-frequency MSI (MSI-H) status reduced survival in patients receiving 5-FU-based adjuvant chemotherapy. Thus, the correlation between MSI status and efficacy of 5-FU-based adjuvant chemotherapy for gastric cancer remains controversial. We performed a PubMed, Embase, and Cochrane search to retrieve studies that explore the correlation between MSI status and 5-FU-based adjuvant chemotherapy efficacy in gastric cancer. After extracting 65 potentially eligible studies, four were ultimately included in this meta-analysis using Stata software (ver. 12.0). For each study, we estimated the hazard ratio (HR) value for overall survival (OS), and HR was extracted per the survival curve in the studies. Heterogeneity was estimated using the random-effects model. Overall, 1174 patients after operation were included: 84 patients were classed as MSI-H and 1090 as microsatellite stable (MSS)/low-frequency MSI (MSI-L). For the four studies, the overall estimate of HR for OS between MSI-H and MSS/MSI-L groups was 1.90 (95% confidence interval: 0.91-3.93; p = 0.08). We found no correlation to exist between MSI status and efficacy of 5-FU-based adjuvant chemotherapy for gastric cancer. Although MSI can effectively predict efficacy of 5-FU-based chemotherapy in patients with colorectal cancer, the correlation between MSI status and efficacy of 5-FU-based adjuvant chemotherapy for gastric cancer remains controversial. This meta-analysis suggests that MSI status is unrelated to efficacy of 5-FU-based adjuvant chemotherapy in gastric cancer, and more prospective clinical studies are needed to further investigate predictive value of MSI status in patients with gastric cancer who, after operation, receive 5-FU-based adjuvant chemotherapy.

Overexpression of TRIP13, a member of the AAA-ATPase family, is linked with various cancers, but its role in metastasis is unknown in colorectal cancer (CRC). In the current study, we investigated the role TRIP13 in experimental metastasis and its involvement in regulation of WNT/β-catenin and EGFR signaling pathways. Evaluation of formalin-fixed paraffin-embedded (FFPE) and frozen tissues of adenomas and CRCs, along with their corresponding normal samples, showed that TRIP13 was gradually increased in its phenotypic expression from adenoma to carcinoma and that its overexpression in CRCs was independent of patient's gender, age, race/ethnicity, pathologic stage, and p53 and microsatellite instability (MSI) status. Moreover, liver metastases of CRCs showed TRIP13 overexpression as compared to matched adjacent liver tissues, indicating the biological relevance of TRIP13 in CRC progression and metastasis. TRIP13 knockdown impeded colony formation, invasion, motility, and spheroid-forming capacity of CRC cells irrespective of their p53 and MSI status. Furthermore, xenograft studies demonstrated high expression of TRIP13 contributed to tumor growth and metastasis. Depletion of TRIP13 in CRC cells decreased metastasis and it was independent of the p53 and MSI status. Furthermore, TRIP13 interacted with a tyrosine kinase, FGFR4; this interaction could be essential for activation of the EGFR-AKT pathway. In addition, we demonstrated the involvement of TRIP13 in the Wnt signaling pathway and in the epithelial-mesenchymal transition. Cell-based assays revealed that miR-192 and PNPT1 regulate TRIP13 expression in CRC. Additionally, RNA sequencing of CRC cells with TRIP13 knockdown identified COL6A3, TREM2, SHC3, and KLK7 as downstream targets that may have functional relevance in TRIP13-mediated tumor growth and metastasis. In summary, our results demonstrated that TRIP13 promotes tumor growth and metastasis regardless of p53 and MSI status, and indicated that it is a target for therapy of CRC.