Breast: Molecular Receptors

Molecular Receptors

Hormonal Receptors

  • Includes:
    • Estrogen Receptor (ER)
    • Progesterone Receptor (PR)
  • Positive Expression Indicates a Better Response to Treatment & Better Prognosis
    • ER+/PR+ is Best > ER-/PR+ is Second > ER+/PR- is Third

Human Epidermal Growth Factor Receptor 2 (HER2)

  • Tyrosine Kinase Receptor
  • Positive Expression Indicates More Rapid Growth & Worse Prognosis

Molecular Subtypes

Luminal Type

  • Accounts for 55-60% – Most Common
  • Expression: ER+ or PR+
  • Subtypes:
    • Luminal A Type (40%) – HER2- & Ki-67 < 14%
      • Best Prognosis of All Molecular Types
    • Luminal B Type (20%) – HER2+ or Ki-67 ≥ 14%

HER2-Enriched

  • Accounts for 10-15%
  • Expression: ER-, PR- & HER2+
  • Worse Prognosis

Basal Type

  • Accounts for 15%
  • Expression: Triple-Negative (ER-, PR- & HER2-)
  • More Common with BRCA1 Mutations