The analysis of ABC transporters (Pgp, MRP1, BCRP) involved in doxorubicin efflux in epithelial mammary MCF10A cells and in a panel of breast cancer cell lines indicated a higher expression of Pgp in TNBC human MDA-MB-231cells, and in murine JC and TUBO cells. The gene discussed is ABCG2; the disease is breast carcinoma.