Multivariate survival analysis revealed that a high expression of IDH2 was an independent poor prognostic factor for DCIS recurrence (HR 2.0; 95% CI 1.1–3.9; p = 0.034) regardless of the other variables including patient age at diagnosis, DCIS size, nuclear grade, presence of comedo necrosis and surgical margin width (Table 3). Here, IDH2 is linked to ductal breast carcinoma in situ.