Breast cancer (BRCA) luminal subtypes (LumA, LumB) had significantly lower levels of leukocytes compared to Basal-like and HER2-Enriched subtypes (Fig. 1E), and within HER2-Enriched subtypes, leukocytes were higher in triple negative breast cancer (TNBC) (Fig. S2D). Here, ERBB2 is linked to triple-negative breast carcinoma.