TAS-102 was approved on September 22, 2015 (US Food and Drug Administration [FDA], 2015) and is indicated for the treatment of patients with metastatic colorectal cancer who have been previously treated with fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, an anti-VEGF (vascular endothelial growth factor) biologic therapy, and if RAS wild-type, an anti-EGFR (epidermal growth factor receptor) therapy (Taiho Oncology, 2015). This evidence concerns the gene EGFR and metastatic colorectal cancer.