ATOX1 and ductal breast carcinoma in situ: From the immunohistochemistry studies, increased expression from matched normal to DCIS (ductal carcinoma in situ) and IDC (invasive ductal carcinoma) were observed for AK1 (8/21 or 38% of all cases) and ATOX1 (10/19 or 53% of all cases) (Figure 4B, lower panel).