Title: Rb deletion in mouse mammary progenitors induces luminal-B or basal-like/EMT tumor subtypes depending on p53 status.

Authors: Jiang, Zhe; Deng, Tao; Jones, Robert; Li, Huiqin; Herschkowitz, Jason I; Liu, Jeff C; Weigman, Victor J; Tsao, Ming-Sound; Lane, Timothy F; Perou, Charles M; Zacksenhaus, Eldad

Published In J Clin Invest, (2010 Sep)

Abstract: Breast cancer is a highly heterogeneous disease, with several different subtypes being characterized by distinct histology, gene expression patterns, and genetic alterations. The tumor suppressor gene retinoblastoma 1 (RB1) is frequently lost in both luminal-B and triple-negative tumor (TNT; i.e., estrogen receptor-, progesterone receptor-, and human epidermal growth factor receptor 2-negative) breast cancer subtypes. However, a causal role for RB1 loss in different subtypes remains undefined. Here we report that deletion of Rb alone or together with its relative p107 in mouse mammary stem/bipotent progenitor cells induced focal acinar hyperplasia with squamous metaplasia. These lesions progressed into histologically diverse, transplantable mammary tumors with features of either luminal-B or TNT subtypes. The TNTs included basal-like tumors as well as tumors that exhibited epithelial-to-mesenchymal transition (EMT). The EMT-type tumors and a subset of the basal-like tumors, but not luminal-B-like tumors, expressed mutant forms of the tumor suppressor p53. Accordingly, targeted deletion of both Rb and p53 in stem/bipotent progenitors led to histologically uniform, aggressive, EMT-type tumors. Reintroduction of Rb into these tumor cells suppressed growth in vitro and tumor formation in vivo. These results establish a causal role for Rb loss in breast cancer in mice and demonstrate that cooperating oncogenic events, such as mutations in p53, dictate tumor subtype after Rb inactivation.

PubMed ID: 20679727

MeSH Terms: No MeSH terms associated with this publication