All the analyzed tumor features differed significantly among the breast cancer IHC surrogates (p < 0.0001).

The surrogates remained predictive of nodal involvement after adjusting for age, tumor size, nodal involvement, EIC and MF/MC.

HER2-neu positivity remained predictive of EIC and MF/MC, after adjusting for HR, age, tumor size, nuclear grade and LVI.

The surrogates had specific patterns of first recurrence that were both time-dependent and site-specific.

Luminal B showed bone as first recurrence site and basal-like showed a low occurrence of nodal metastasis. Higher rates of visceral recurrence occurred among basal-like and HER2-neu+, translating in shorter DFI.