PIK3CA and cancer: The amplified chromosome 3q region contains several genes with relevance to cancer, such as the phosphoinositide-3-kinase catalytic alpha polypeptide gene (PIK3CA) at 3q26.32 [12], the telomerase RNA component gene (TERC) at 3q26.2 [13], [14], the retinol-binding protein 1 and 2 genes (RBP1-RBP2) at 3q23, the TP63 gene at 3q28 [15], and the sex-determining region Y-box 2 gene (SOX2) at 3q26.33 [16]–[18].