GNAS and ductal breast carcinoma in situ: At an individual gene level, 16 genes (FGFR2, BRCA2, ATM, MLL3, GNAS, NOTCH1, PDGFRA, SMARCA4, NTRK3, PCM1, CLTCL1, FANCE, BCOR, MKL1, NACA and PMS1) in the cancer Gene Census were exclusively observed in DCIS-IDC (1–7 genes per case), but not in pure DCIS (Figure 3).