In summary, a high-protein diet promoted the growth of human LuCaP23.1 and WHIM16 tumors in mice, and a reduction in protein intake resulted in a significant inhibition of tumor growth even when the diet was started after the formation of measurable tumors, possibly through inhibition of the IGF/Akt/mTOR pathway and epigenetic modifications. The gene discussed is IGF1; the disease is neoplasm.