Context: Breast cancer (BC) risk has been differentially associated with urinary levels of some phthalate metabolites.
Objective: To investigate whether PPARγ and PPARGC1B polymorphisms modulate these associations.
Materials and methods: 208 BC cases were age-matched with 220 population controls. Phthalate metabolites were determined by HPLC-MS. PPARγ Pro12Ala (rs1801281) and PPARGC1B Ala203Pro (rs7732671) and Val279Ile (rs17572019) were genotyped.
Results: The association between mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and BC risk was positively modified in PPARγ Pro12Ala C carriers. The association with mono-iso-butyl phthalate (MiBP) in PPARGC1B Ala203Pro G carriers was negatively modified.
Conclusion: PPARγ and PPARGC1B polymorphisms modulate the association between phthalate exposure and BC risk.