ESR1 and breast neoplasm: Here, sera of obese ERα+ patients induced the expression of COX-2 in macrophages, leading to greater aromatase expression by pre-adipocytes (148); then, aromatase that was released by macrophages/pre-adipocytes grown with sera derived from obese patients, induced in ERα+ breast tumor cells the activity of ERα, tumor cell migration, and proliferation (148).