We next explored the association of BCR and TCR repertoires with hormone receptor status, PAM50 subtypes, and TIL levels, scored as % of the intratumoral stroma area following the International TILs Working Group guidelines36, in order to depict the heterogeneity of the immune response within HER2-positive breast cancer and evaluate whether BCR/TCR measures could add additional information to TILs. The gene discussed is ERBB2; the disease is breast carcinoma.