ESR1

Type

Gene (protein-coding, hormone receptor)

Description

ESR1 (Estrogen Receptor 1) encodes the estrogen receptor alpha (ERα), a ligand-activated transcription factor and the defining biomarker of hormone receptor-positive breast cancer. Activating ESR1 mutations (e.g., Y537S, D538G) confer ligand-independent receptor activity and are a major mechanism of acquired resistance to aromatase inhibitors. These mutations are detectable via ctDNA and emerge under selective pressure from endocrine therapy.

External identifiers

• HGNC: 3467
• NCBI Gene: 2099
• UniProt: P03372

Wiki sources

• wander2026-ctdna-cdk46-breast-cancer — ESR1 mutations detected by ctDNA in HR+ breast cancer