At these respective times, 100% (20/20) of DIO and 90% (18/20) of control mice that had been injected with Wnt-1 p53+/− mammary tumor cells had palpable tumors, and 80% (16/20) of DIO and 55% (11/20) of control mice had palpable Wnt-1 p53+/+ tumors. This evidence concerns the gene WNT1 and breast cancer.