Thyroid cancers frequently harbor activating mutations in the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways, as represented by RET/PTC, RAS and BRAF mutations in the former and by PIK3CA and PTEN mutations in the latter (3,4). Here, PIK3CB is linked to thyroid cancer.