PIK3CA and medullary thyroid gland carcinoma: Classical examples include BRAF mutation in PTC and ATC [3], [4], Ras, PIK3CA (encoding PIK3CA–the p110α catalytic subunit of phosphatidylinositol 3-kinase or PI3K), and PTEN mutations in benign thyroid neoplasia, FTC and ATC [5]–[8], and RET mutation in MTC [9].