ERBB2 and breast carcinoma: Following thorough IMC panel validation in the “test-TMA” setting, where it has been concluded that the panel has displayed overall good quality and concordance with the IHC staining, the complete panel was used for staining of “pilot-TMA”, consisting of five cases of Luminal, four cases of triple negative, and one case of HER2 enriched breast cancer subtypes (each case represented by multiple numbers of cores) (Supplementary Table 2).