In the control group, only 10% had mammary tumors and disease onset was significantly later (Stat1−/−: 394.5 days ± 13.52 and Stat1+/+: 479.3 days ± 11.46; **P = 0.0089; values represent mean ± SEM) (Fig. 1A and 1B). This evidence concerns the gene STAT1 and breast cancer.