The positive rate of Mortalin protein was significantly higher in breast cancers (78.1 %, 121/155) than either in DCIS (53.8 %, 28/52) or in adjacent normal breast tissues (28.9 %, 13/45) (P < 0.01 and P < 0.05, respectively). Here, HSPA9 is linked to ductal breast carcinoma in situ.