KRT5 and ductal breast carcinoma in situ: Notably, SMMHC and p63 staining were retained at the periphery of DCIS acini adjacent to DCIS-like IDC acini (Figures 3B–C for SMMHC and Figures 3E–F for p63), whereas CK5/6 and S100 staining were lost in the same regions (Figures 3H,I,K,L).