RET and thyroid gland papillary carcinoma: Papillary and follicular thyroid cancers are hypothesized to develop via distinct mutation pathways, with more than 70% of papillary thyroid cancers caused by mutations of the RET/RAS/BRAF/MAPK pathway, and more than 80% of follicular thyroid cancers caused by mutations of the RAS genes or PAX8/PPARgamma translocations [68].