Abstract SY02-01: Regulators of in situ to invasive breast carcinoma progression.

Abstract

Abstract A major clinical diagnostic criterion that differentiates in situ from invasive breast carcinoma is the presence of a continuous myoepithelial cell layer and basement membrane. In pre-invasive lesions such as DCIS, a relatively intact myoepithelial cell layer and basement membrane are still observed, but we have found that the molecular profiles of DCIS-associated myoepithelial cells are distinct from those from normal breast. The mechanisms underlying the loss of myoepithelial cells during the in situ to invasive breast carcinoma transition are unknown. We hypothesized that the differentiation of breast epithelial progenitors into myoepithelial cells is progressively inhibited by signals from tumor epithelial cells and cells composing the microenvironment such as fibroblasts and leukocytes. As a consequence, the myoepithelial cell layer is progressively lost and eventually disappears resulting in progression to invasion. We have been testing this hypothesis by characterizing myoepithelial cells from normal human breast tissues from nulliparous and parous women, including BRCA1 and BRCA2 mutation carriers. To dissect the functional properties of different types of myoepithelial cells, we have been using the MCFDCIS xenograft model. Our results will not only improve the current understanding of the role of myoepithelial cells but also have the potential to provide new prognostic markers to predict risk of invasive progression in DCIS. Furthermore, our results may help identify new targets for chemoprevention aimed at decreasing the risk of invasive breast tumors. Citation Format: Kornelia Polyak. Regulators of in situ to invasive breast carcinoma progression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr SY02-01. doi:10.1158/1538-7445.AM2013-SY02-01