PIK3CA and gastric cancer: Target sequencing of 46 cancer-related genes was conducted for the 90 gastric cancers, and 47 cancers (52%) had 68 somatic point mutations of 15 different genes (TP53, KRAS, PIK3CA, ERBB2, FBXW7, SMAD4, CTNNB1, ERBB4, PTPN11, SMARCB1, BRAF, GNAS, NOTCH1, NRAS, and PTEN) (Tables 1 and 2).