PIK3CA and neoplasm: Moreover, we investigated the KRAS/BRAF/GNAS/PIK3CA mutational status (mutational analysis for exon 2 of KRAS, exon 15 of BRAF, exons 9 and 20 of PIK3CA, and exons 8 and 9 of GNAS) of the original tumor (pancreatic head) and the recently resected tumors from the pancreatic body and tail.