We observed an increased level of total IgM and IgG and a reduced level of IgA in the sera of young (2 months) and aged (11 to 20 months) male BC-CosmcKO mice (Fig. 2A) (23), and an altered immunoglobulin profile was also observed in young female BC-CosmcKO mice (Fig. 2B). Here, CD40LG is linked to breast cancer.