Incidence of Microsatellite Instability, Mutational Burden, and Actionable Alterations in Genes of Patients with Metastatic Colorectal Carcinoma: A Study from a Tertiary Care Hospital in India

Background and objective: Tumor mutational burden (TMB) microsatellite instability (MSI) are predictive clinical markers of responses to immunotherapy in a wide range advanced cancers, including colorectal cancers. The data about TMB MSI Indian patients is scarce. Hence, assessed the incidence MSI, TMB, actionable alterations genes with metastatic carcinoma. Methods: A single centre, observational, prospective study newly diagnosed (n=60) carcinoma were for incidence, burden, genes. Results: ranged between 5.08 2391 mutations per megabase, 12 (20%) had low intermediate 36 (60%) high TMB. was right-sided than left-sided cancer (100% vs. 47%). Three or more two, one genomic alteration observed 26 (44%), 20 (33%), patients, respectively. Gene fusion absent all 60 patients. predominant but statistically insignificant (p=0.7). APC, TP53, BRCA2 gene evident 46, 28, 22 Wild KRAS/NRAS cancers (n=22) presented at baseline. There no significant correlation age, sex, histology, tumor differentiation. Conclusion: This highlights importance detecting earliest. Genomic should form basis customizing exploring newer targeted therapy against most common like RAS improve outcomes.