To determine if AHR control of stem cell characteristics is generalizable to this cancer subtype, SUM149 cells, derived from an IBC, were studied for expression of Ahr and Cyp1b1 in ALDHhigh and ALDHlow subpopulations, for the contribution of the AHR to ALDH1 activity, and for the ability to form tumorspheres. The gene discussed is CYP1B1; the disease is cancer.