SLC40A1 and ductal breast carcinoma in situ: However, in breast carcinoma samples, lymphocytes and macrophages expressed significantly higher levels of FPN1 than in normal samples (p = 0.014 and p < 0.001, respectively) (Fig. 2b,c), with FPN1 expression in macrophages being higher in DCIS samples (p < 0.01 when compared with IDC samples) (Fig. 2b).