CD40 and breast carcinoma: As for B lymphocytes, breast carcinoma cell survival is affected by CD40L in a complex manner: soluble CD40 ligand has been reported to inhibit the growth of breast carcinoma cell lines while membrane bound CD40L enhances Fas mediated apoptosis; conversely, stimulation of CD40+ breast carcinoma cells inhibited paclitaxel-induced apoptosis [32,35,38,39].