PIK3CA and colorectal carcinoma: In one study that included few patients with stage IV disease and BRAF mutations, the latter were associated with limited survival in patients with microsatellite-stable (MSS) disease (Samowitz et al, 2005); mutations in exons 9 or 20 of the PIK3CA gene are associated with lower relapse-free survival in patients with stage II or III CRC (Kato et al, 2007).