Therefore, the aim of this study was to assess the modifying effect of genetic variants in 10 energy homeostasis genes (ADIPOQ, CART Prepropeptide (CARTPT), CCK, GHRL, LEP, LEP receptor (LEPR), MBOAT, melanocortin-4-receptor gene (MC4R), NPY and proopiomelanocortin (POMC)) on the association of serum concentrations of IGF-1 and IGFBP-3 with the risk of BC. This evidence concerns the gene MC4R and breast cancer.