RET and familial medullary thyroid carcinoma: Hereditary MTCs occurs in multiple endocrine neoplasia (MEN)2, which is further subcategorized into MEN2A, MEN2B, and familial MTC (FMTC) based on the phenotype such as pheochromocytoma, hyperparathyroidism and/or other developmental anomalies (infertility, marfanoid habitus, etc.; Wells et al., 2013; Tomuschat and Puri, 2015).