TP53 and cancer: The p53 is an important protein that regulates the cell cycle and functions as a tumor suppressor.65 Studies showed ~50% human cancers have alterations in the p53 gene which results in the inactivation of p53 function or loss of p53 expression.66 The mouse double minute 2 (MDM2) is a proto-oncogene and a key negative regulator of p53.