To explore whether CD239 could serve as a target antigen for diagnosis and therapy of breast cancer, we (a) immunohistochemically analysed CD239 expression in breast cancer tissues; (b) examined internalization of CD239 into malignant breast cancer cells in vitro; (c) produced a human scFv-Fc antibody (C7-Fc) against CD239; and (d) investigated the efficacy of C7-Fc as the basis for a novel ADC in vitro. This evidence concerns the gene BCAM and breast carcinoma.