Characterization of tumor-associated-macrophage of breast cancer patient-derived xenografts

The aim of this study was to characterize the stroma displayed by different models of breast cancer tumors in mice. For this purpose, transcriptomic and flow cytometry analyses on murine populations were performed in a series of 25 PDXs and 2 most commonly used GEMs (MMTV-PyMT and MMTV-erBb2). Specifically, macrophages from 5 models were sorted and profiled by gene expression and phenotypically characterized by flow cytometry. Composition of hematopoietic cells, mainly macrophages and granulocytes, varied tumor from tumor. Macrophages were shown to display specific polarization phenotype related to M1/M2 classification and associated with genes implicated in recruitment, invasion and metastasis processes. The heterogeneity of stroma component of the studied models suggests that tumor cells educate their microenvironment to fulfill their needs. This observation therefore supports the relevance of such models for preclinical study purposes. Macrophage/monocyte-like cells (EpCAM-CD45+F4/80+) were sorted on a FACS