Regarding TFR1 expression, a significantly higher expression was seen in macrophages of negative PR DCIS cases (n = 15; p = 0.039) and in lymphocytes and macrophages of HER2 positive IDC cases (Ly: n = 79; p = 0.028; M0: n = 79; p = 0.003). Here, ERBB2 is linked to ductal breast carcinoma in situ.