Because Treg infiltration in both melanoma (Miracco et al., 2007; Tefany et al., 1991) and breast cancer (Bates et al., 2006; Gobert et al., 2009) has been associated with poor prognosis, we investigated whether any of the applied cancer models in BRGS‐HIS mice recruited Tregs (FoxP3+) cells. The gene discussed is FOXP3; the disease is breast carcinoma.