This enzyme, which is responsible for the extraglandular synthesis of estrogens from C19 steroids, is increased in the presence of adipose tissue inflammation, being inducible by TNF-α, IL-6, insulin and prostaglandin E2, and has been associated with an increased ER-positive breast cancer risk in obese postmenopausal women [2,8]. The gene discussed is ESR1; the disease is breast cancer.