Absence of MDM‐2 gene amplification in experimentally induced tumors regardless of p53 status

Abstract
To assess the generality of the hypothesis that murine double‐minute‐2 (MDM‐2) gene amplification complements the absence of p53 mutation during tumor development, we analyzed 143 murine tumors induced by a variety of carcinogenic agents in two different mouse strains. Only three of 143 tumors showed p53 genetic alterations and none showed MDM‐2 amplification, indicating the existence of alternative pathways that permit tumor cells to bypass p53–MDM‐2 control.