Characterization of medroxyprogesterone and DMBA-induced multilineage mammary tumors by gene expression profiling

Mouse mammary tumors arising during medroxyprogesterone‐DMBA‐mediated mammary carcinogenesis comprised three distinct phenotypes: adenocarcinoma, squamous cell carcinoma, and myoepithelial carcinoma. The molecular signature for each of the three tumor subsets was characterized by gene microarray analysis, and three distinct sets of gene expression profiles were obtained that were corroborated in part by quantitative RT‐PCR and immunohistochemistry. These results suggest that this carcinogenesis and gene expression model will be useful for rapidly assessing the histopathological differences arising in mammary carcinogenesis and the effects of tumor promoting or chemoprevention agents. Published 2005 Wiley‐Liss, Inc.