KRAS and colonic neoplasm: Right-sided colon cancer is characterized by the alterations in BRAF, KRAS, and PIK3CA, and has a higher rate of deficient mismatch repair; whereas instability pathway-related APC and TP53 mutations are more frequently observed in left-sided colon cancer, which has a better response to both chemotherapies and targeted therapies, thus showing better prognosis in patients (28, 29).