Step-changing proteins were identified in DCIS compared with cancer-adjacent and normal tissues, including increased expression of STAM, ARF5, ANXA6, SCPEP1, ME2, and WFS1 (Supplementary Table 6), and decreased expression of KRT1, KRT10, KRT6E, APOA1, DSP, LUM, ANK1, and F2 in DCIS tissues (Supplementary Table 6). This evidence concerns the gene APOA1 and ductal breast carcinoma in situ.