GDF15 and breast cancer: One such cytokine is MIC-1/GDF15, a divergent member of the transforming growth factor-β (TGF-β) superfamily [2] that is over-expressed by many patients with common cancers including those of the prostate and can be further induced by cancer therapies including surgery, chemo and radio-therapy of prostate, colon and breast cancer [3]–[9].