PIK3CA and colorectal cancer: We focused on genes which likely play a role in the later stage of carcinogenesis, such as TP53 and PIK3CA. Mutations in both these genes are considered late events and occur in a substantial proportion of colorectal cancer, with approximately 70% of sporadic tumors harboring TP53 mutations [6] and around 25% harboring PIK3CA mutations [7,8].