CD47 and breast cancer: However, in the case of breast cancer the downstream SE associated with CD47 is only present in two of seven tested breast cancer lines: MCF7 (Estrogen Receptor positive (ER+) and Progesterone Receptor positive (PR+) subtype) and HCC1954 (Human Epidermal Growth Factor positive (Her2+), ER−, PR− subtype) (Fig. 1a).