The correlation between the molecular subtypes (Luminal A, Luminal B, HER2-enriched and Basal-like) by PAM50 and immunohistochemistry (IHC) surrogates using modified median (A) and subgroup-specific (B) gene centering methods. When the Luminal subtypes were grouped together, the correlation between PAM50 and IHC improved to fair agreement using modified median (C; accuracy = 0.81, kappa = 0.53) and subgroup-specific (D; accuracy = 0.79, kappa = 0.49) gene centering methods. IHC surrogates were defined as: Luminal A – ER+ and/or PR+, HER2-, and Ki-67 low (or histologic grade 1 or 2); Luminal B – ER+ and/or PR+, and HER2+; or ER+ and/or PR+, HER2-, and Ki-67 high (or histologic grade 3); HER2-enriched – ER-, PR- and HER2+; Basal-like – ER-, PR-, HER2-, and CK 5/6+ and/or EGFR+.