In an elegant study which placed tumor bearing mice on a fasting mimicking-diet (FMD), the authors observed lowered HO-1 expression by the tumor cells, which rendered tumors more sensitive to doxorubicin and cyclophosphamide in the 4T1 model of breast cancer, and to doxorubicin in the B16 melanoma model, which resulted in CD8+ T-cell mediated tumor control associated with a loss of Tregs (130). The gene discussed is CD8A; the disease is breast carcinoma.