In patients with metastatic colorectal cancer treated with CT or best supportive care (BSC), the OS was 6.1 vs. 4.6 months, but when the KARS mutation is taken in account, there is an OS increase for a wide-type KRAS patients, 8.6 vs. 5.0 months. The gene discussed is KRAS; the disease is metastatic colorectal cancer.