PPARGC1A and colorectal carcinoma: Logistic regression analyses of associations between PPARG rs3856806 C>T, PPARGC1A rs2970847 C>T, rs8192678 C>T, rs3736265 G>A, and PPARGC1B rs7732671 G>C and rs17572019 G>A polymorphisms and risk of CRC.