Morphologic, molecular and microenvironment factors associated with stromal invasion in breast ductal carcinoma in situ: Role of myoepithelial cells.

Background: Ductal carcinoma in situ is the last step preceding invasive ductal carcinoma in breast carcinogenesis.
Objective: We investigated the role of myoepithelial cells and epithelium characteristics as predictors of the risk of stromal invasion.
Methods: We selected 236 cases with initial diagnosis of DCIS followed by surgical ressection distributed in groups 1 (without invasion) and 2 (with invasive carcinoma).
Results: The risk of stromal invasion after a DCIS diagnosis in biopsy was associated to triple-negative profile and loss of CD10 expression by myoepithelial cells, and inversely associated with CK5/6 expression by neoplastic cells and high expression of Smooth Muscle Myosin Heavy Chain (SMMHC) by myoepithelial cells.
Conclusions: A combination of characteristics of epithelial and myoepithelial cells in DCIS in biopsy specimens is related to the risk of stromal invasion.