It has been estimated that approximately 10%–20% of all patients with colorectal cancer have either KRAS codon 61, KRAS codon 146, BRAF, NRAS, or PIK3CA gene mutations, suggesting that approximately 60,000–120,000 patients (10%–20% of the 600,000 who die annually from colorectal cancer) worldwide could be screened by this expanded mutation test. Here, PIK3CA is linked to colorectal cancer.