However, Van Cutsem et al. investigated chemotherapy outcome in K-ras patients with metastatic colorectal cancer and showed that there was no significant difference in progression-free survival or overall survival between patients who received cetuximab plus irinotecan, fluorouracil, and leucovorin (FOLFIRI) or FOLFIRI alone [19]. Here, KRAS is linked to metastatic colorectal cancer.