PIK3CA and esophageal squamous cell carcinoma: A recent study on ESCC in Japan has highlighted the roles of multiple recurrently altered genes in the pathogenesis of ESCC, including those that regulate the cell cycle (TP53, CCND1, CDKN2A, FBXW7); epigenetic processes (MLL2, EP300, CREBBP, TET2); and the NOTCH (NOTCH1, NOTCH3), WNT (FAT1, YAP1, AJUBA), and receptor-tyrosine kinase phosphoinositide 3-kinase signaling pathways (PIK3CA, EGFR, ERBB2) [7].