miR-1301 was predicted to target the CDKN1B tumor suppressor gene, whose inactivating mutations are responsible for MEN4 syndrome, the RET oncogene, whose activating mutations are responsible for the multiple endocrine neoplasia type 2 (MEN2) syndrome, the AP2S1 gene, whose loss-of-function mutations have been associated with familial hypocalciuric hypercalcemia type 3, the CCND2 gene encoding cyclin D2 a positive regulator of cell cycle, and the CTNNB1 gene encoding the catenin beta 1, involved in the regulation of cell adhesion. The gene discussed is CCND2; the disease is multiple endocrine neoplasia type 2.