SCPEP1 and ductal breast carcinoma in situ: For DCIS tissues, compared with both DCIS cancer-adjacent and normal tissues, we detected four up-regulated (GAPDH, HSPA9, CCT4, and SCPEP1) (Supplementary Table 4) and 48 down-regulated proteins (including KRT10, APOA1, ALDH1A1, and others) (Supplementary Table 5) in DCIS tissues.