However, although the risk of developing extra-thyroidal malignancy in non-Cowden’s syndrome is documented [21,22], the clinical correlation between sporadic breast cancer (20% of which are HER2+) [23] and PTC is still controversial [24,25], and the co-occurrence of both disorders in the same individual is a subject of extensive debate [26,27]. Here, ERBB2 is linked to breast cancer.