KRAS mutations and their associations with clinicopathological features and survival in Vietnamese non‑polyp colon cancer patients

The aim of the present study was to determine Kirsten Ras sarcoma virus (KRAS) mutations and the associations of KRAS mutations with clinicopathological features and treatment outcomes in Vietnamese non-polyp colon cancer (NPCC) patients. The data in the present study covered 194 patients with non-polyp colon cancers at stages II or III, according to the 8th edition of the American Joint Committee on Cancer staging system, in northern Vietnam from January 2016 to August 2020. All patients underwent radical surgery and adjuvant therapy with FOLFOX4 or XELOX. Subsequently, the recruited patients were followed-up with scheduled hospital exams for diagnosing recurrence. Genomic DNA samples were prepared from dissected tumors and specific sequences of the KRAS gene were amplified by polymerase chain reactions (PCR). The mutations at codons 12, 13, 59, 60, 61, 117 and 146 of the gene were determined. Possible associations of the KRAS mutations with clinicopathological properties and the survival of patients were analysed. The KRAS mutation rate was 47.9% in Vietnamese patients with NPCC, of those, mutations in exon 2 accounted for 91.4% of all detected mutations. The mutated-KRAS patients exhibited a significantly higher rate of anemia. Moreover, the KRAS mutation rate was higher in females (57.1%) than in males (39.8%). The KRAS mutation rate was also higher in patients with right colon cancers. Furthermore, KRAS mutations were an independent prognosis for poor disease-free survival (DFS) and overall survival (OS) in stage II patients. Among left-sided colon patients, mutated KRAS was a significant predictive factor for poor DFS but not for OS. The present study revealed a very high mutation rate of KRAS in Vietnamese patients with NPCC. The data of the present study indicated that the mutation status was associated with female patients and right-sided tumors. The KRAS mutations were a negative factor for the survival of patients with stage II NPCC and patients with left-sided colon cancer.