In 2019, Morgan et al. discovered that the transactivation of ERE was heightened in the ER-positive MCF-7 breast cancer cell lines co-cultured with adipose stromal cells from individuals with obesity due to increased aromatase expression, further showing the amplified effect of estrogens on breast cancer progression in obesity [153]. Here, CYP19A1 is linked to obesity due to melanocortin 4 receptor deficiency.