Weight gain increases human aromatase expression in mammary gland

► Aromhum mice fed a high fat diet vs normal chow had a larger mammary gland mass. ► Had elevated human aromatase mRNA levels via promoters I.4 and II in mammary gland. ► Expressed human aromatase at same sites: adipose fibroblasts and myoepithelial cells. ► Had increased TNFα and C/EBPβ expression in mammary gland. ► Exhibited no change in human aromatase mRNA levels in gonadal white adipose tissue.