Estrogen receptor (ER) and aromatase (CYP19A1) (ER/CYP19A1)

The estrogen receptor (ER) and aromatase (CYP19A1) are distinct but functionally linked proteins central to estrogen-dependent signaling and biosynthesis. The estrogen receptor is a ligand-activated nuclear transcription factor that regulates the expression of genes involved in cell proliferation, particularly in mammary and uterine tissues [1]. Aromatase is a member of the cytochrome P450 superfamily and serves as the rate-limiting enzyme that catalyzes the conversion of androgens into estrogens [2]. In clinical practice, these targets are often addressed together or sequentially, especially in the treatment of hormone receptor-positive breast cancer, where reducing estrogen levels or blocking its receptor is therapeutic [3]. Pharmacological interventions include Selective Estrogen Receptor Modulators (SERMs) like tamoxifen, Selective Estrogen Receptor Degraders (SERDs) like fulvestrant, and Aromatase Inhibitors (AIs) like letrozole [4]. While effective in suppressing tumor growth, targeting these proteins can lead to adverse effects such as bone loss, joint pain, and vasomotor symptoms due to systemic estrogen deprivation [5].

Other names

ESR1ESR2CYP19A1Estrogen synthetaseER-alphaER-beta

Selective estrogen receptor modulation (SERM), selective estrogen receptor degradation (SERD), and aromatase inhibition (AI) to block estrogenic signaling and production.