TFAP2C and breast cancer: In breast cancer, TFAP2C regulates the sensitivity to peroxide by mediating the expression of GPX1. GPX1 expression is enhanced by TFAP2C via the TFAP2 regulatory region within the GPX1 promoter (methylation of the CpG island within the TFAP2 regulatory region leads to reduced binding activity and decreased GPX1 expression) [129].