MDM2 and parathyroid gland carcinoma: Following the advent of tissue microarrays, a study concluded that the combined positivity of p27, B-cell lymphoma 2 (bcl-2), and mouse double minute 2 homolog (mdm2) adjoined by a low Ki-67 proliferation index indicated a benign clinical behavior of any given parathyroid tumor, as this profile was not evident in any parathyroid carcinoma but found in the vast majority of adenomas [136].