FAS and Burkitt lymphoma: Estrogens also induce in vitro increases in IgA, IgG1, IgG3 and IgE levels in mouse spleen B cells; increase the frequency of mutations in the VH and CD95/Fas loci of the Burkitt lymphoma cell line (Ramos); and cause mutations in the Sγ3 region of spleen cells from the intersection of AID−/− and BALB/c mice (73).