Effects of MMR Protein and BRAF V600E Mutation on Survival of Sporadic Young-Onset Colorectal Cancer Cases

The effect of mismatch repair (MMR) protein and the b-type raf proto-oncogene (BRAF) mutation on survival of young-onset sporadic colorectal cancer (CRC), is debatable. This study aimed to determine the survival of sporadic young-onset CRC cases with MMR protein and BRAF mutation cases in Kelantan. The retrospective cohort study comprised 31 sporadic young-onset CRC cases diagnosed before age 40. Patients' information was extracted from the medical records unit and laboratory information system (LIS). Cases with hereditary CRC, inflammatory bowel disease, concurrent non-colonic cancer and cases under 18 years old were excluded from the study. The Kaplan–Meier survival analysis was used to determine the survival time of CRC cases. The mean age of sporadic young-onset CRC cases was 31.5-year with most were female (61.3%). The majority (41.9%) of cases complained of abdominal discomfort as their primary presenting symptom. Most of cases had a tumour located on the right side of colon (71.0%) and moderately differentiated adenocarcinoma (83.9%). More than half (54.8%) were in stage iv when presented to the hospital. The pattern that is most common was a positive expression in all MMR proteins that made up the group of microsatellites stable (MSS) (64.5%). Microsatellite instability (MSI) was high in nine cases (29.0%) and low in two cases (6.5%). 83.9% of the patients showed positive BRAF v600e expression. The overall median survival time of sporadic young-onset CRC cases was 4.1 years (95% confidence interval (CI): 2.59, 5.62). Histology subtypes and BRAF v600e mutation were found to affect the overall survival of sporadic young-onset CRC cases. Most sporadic young-onset CRC cases were microsatellite stable and displayed positive BRAF V600E. Diagnosis at an early stage would improve survival, in general, among cases with CRC. The most typical symptoms of sporadic young-onset CRC were abdominal discomfort and an advanced cancer stage. Histology subtypes and BRAF V600E mutation affected the overall survival. There is a need for more research involving a wide range of clinical and biological factors.