A large-scale genome analysis of more than 3000 tumors from 12 different cancer lineages found that mutations in TP53, DNTM3A, and PIK3CA occurred early, contributing to the initiation of carcinogenesis, whereas mutations in K-Ras and N-Ras occurred later and were associated with cancer progression rather than initiation [21,22]. Here, PIK3CA is linked to cancer.