Of the total 16 proteins that significantly changed from preneoplastic to DCIS, we identified 6 proteins (FoxO3a_ pS318_S321, Bcl-xL, Cyclin-B1, MEK2, 4E-BP1_pS65 and S6_pS235_S236) that showed a pattern of continuous and significant change across the model system through to DCIS, the final targetable step for prevention of invasive disease (Fig. S2B). Here, MAP2K2 is linked to ductal breast carcinoma in situ.