CD44 and breast carcinoma: To verify the in vitro cytotoxicity the mouse anti-rCD44v antibody, human breast cancer MCF7 (CD44+ cell line), and human normal HEK293 (CD44− cell line) were treated with a spectrum of the purified antibody concentrations (2 to 0.125 μg) based on the amount of absorptions ELISA test (Fig. 3a, b).