Molecular Subtypes

The 13th St Gallen International Breast Cancer Conference (2013) Expert Panel recommends the use of four biomarkers for molecular subtyping of breast cancer:

• ERBB2 (HER2, human epidermal growth factor receptor 2)
• ESR1 (estrogen receptor 1)
• PGR (progesterone receptor)
• MKI67 (marker of proliferation Ki-67, a marker expressed in proliferating cells)

Based on recommendations of the St Gallen Consensus group, these markers are used to identify 5 distinct subtypes:

• Luminal A-like
• Luminal B-like (HER2 negative)
• Luminal B-like (HER2 positive)
• HER2 positive (non-luminal)
• Triple negative (ductal)

Each of these subtypes is associated with a clear therapy recommendation and distinct characteristics of the patient’s prognosis.