A study on the relationship among DNA methylation, PAH-DNA adducts, and breast cancer was carried out in 2015 by White et al. Thirteen genes were identified associated with breast cancer occurrence, and that the tumor suppressor gene retinoic acid receptor beta (RARβ) and the adenomatous polyposis coli (APC) promoter specific methylation interacted with PAH-DNA adducts, which affected the hormone receptor expression, and increased the risk for developing breast cancer [144]. This evidence concerns the gene NR4A1 and breast cancer.