RET and Hashimoto thyroiditis: However, its specificity has been questioned because of the identification of RET/PTC in non-neoplastic follicular cells in Hashimoto’s thyroiditis (HT), oncocytic tumors, and other benign lesions, and this expression variability should be taken into account for the molecular diagnosis of thyroid lesions (Cinti et al. 2000; Elisei et al. 200; Nikiforova et al. 2002; Rhoden et al. 2004).