Table 1

Surrogate definitions of molecular subtypes of breast cancer

Molecular subtypesLuminal ALuminal BHER2-overexpressionBasal-like
Histopathological surrogate definition

  • ER-positive

  • HER2-negative

  • Ki67 low

  • PR high*

HER2-negative

  • ER-positive

  • HER2-negative

  • and either

    • Ki67 high† or

    • PR low

  • HER2-positive

  • ER-positive

  • HER2-positive

  • any Ki67

  • any PR

HER2-positive (non-luminal)

  • HER2-positive

  • ER and PR absent

Triple-negative (ductal)

  • ER and PR absent

  • HER2-negative

  • *The cut-off value is 20% for PR high expression.

  • †The cut-off value is 14% for Ki67 high expression.

  • ER, oestrogen receptor; HER2, human epidermal growth factor receptor 2; PR, progesterone receptor.