Fisher’s exact test revealed that total CTCs (less than 3), mCTCs (less than 2) and DFS (60 months or more) correlated with long PFS, as well as other clinicopathological factors such as age, tumour grade, ER and HER2 status, metastatic site (visceral vs non-visceral), and previous chemotherapy (Additional file 2: Table S2). Here, ERBB2 is linked to neoplasm.