KRAS and rectal cancer: mt-KRAS was not associated with pCR or the NAR score; however, mt-KRAS was independently associated with a worse prognosis and survival.169 In a meta-analysis reviewing the impact of mutations in genes such as TP53, RAS, SMAD4, PIK3CA, and BRAF and the MSI status on response to treatment and prognosis, in locally advanced rectal cancer (LARC), KRAS mutations were associated with a greater risk of nonresponse following preoperative radiation therapy in LARCs (OR = 1.80, 95% CI: 0.39–20.05).