RESUMEN
OBJECTIVES: This review focused on the possible mediatory role of the FTO in the association between obesity and breast cancer. METHOD: All articles published in English from June 1990 to January 2017 were studied. The search terms used were FTO gene, FTO polymorphism, breast cancer, and obesity. Inclusion criteria consisted of assessment of the relationship between FTO polymorphisms and/or FTO expression level with obesity and/or breast cancer as a primary outcome. RESULTS: The FTO gene may have a role in the cellular sensing of macronutrients. Over expression of the FTO gene increases the levels of mammalian target of rapamycin (mTOR) signaling that is a key regulator of cell growth. Moreover, some SNPs in intron locations of the FTO gene exert their effects on body mass index, body composition and breast cancer risk through change of the homeobox transcription factor iriquois 3 (IRX3) gene expression level. CONCLUSION: The FTO gene may has a critical role in obesity and breast cancer. Similar molecular mechanisms may play a role in the development of breast cancer and obesity. If this result is correct then, it will be interesting to examine the FTO gene as a molecular therapeutics target.