Additionally, Niikawa et al. reported that estradiol was locally produced, mainly by aromatase, in lung cancer cells and it played an important role in the growth of ER-positive tumors in in vitro studies, thereby suggesting that anti-estrogen therapies (such as selective ER modulators and aromatase inhibitors) may be clinically effective in patients with ER-positive lung cancers [55]. The gene discussed is ESR1; the disease is lung carcinoma.