Influence of the Breast Tumor Stromal Fibroblasts on Immunological Processes In Vitro

The effects of stromal cell cultures isolated from breast cancer tissue on the differentiation and maturation of dendritic cells and proliferation of lymphocytes were studied in vitro. The derived cultures had the fibroblast-like morphology and carried mesenchymal markers CD73 and CD90 in the absence of epithelial (CD326, CD24) and macrophage (CD68) markers. The cells also expressed CD44, CD10, and CD29 and had low levels of HLA-ABC expression. Intracellular expression of fibroblast activation protein (FAP), tenascin C, and α-SMA indicated their activated state and stromal origin. Analysis of the functional properties of the cells revealed their ability to suppress differentiation of dendritic cells from monocytes, as well as the proliferation of T lymphocytes. However, they had no significant effect on DC maturation. The results demonstrate that fibroblasts in the tumor stroma of breast cancer may have a suppressive effect on important mechanisms of the adaptive immunity and can be involved in the process of tumor escape from the immunological control.