In the ARTemis + PBCP cohort (dominated by ER-positive, HER2−negative (ER+,HER2−) BC), the prominent contributors to chemotherapy response were CAFs, normal epithelial and malignant cells (Figure 2E,H), whereas in the TNBC-specific BrighTNess cohort, the key players were myeloid, plasmablasts and malignant cells (Figure 2F,I). Here, ERBB2 is linked to breast cancer.