Interestingly, the group of patients (Patients 1, 4, 8 and 10) diagnosed as having HER2+ tumours that were subjected to anti-HER2 therapy, in between the two moments of blood collection, were confirmed positive for HER2+ CTCs at the baseline; however, they showed no HER2+ CTCs at the follow-up, suggesting the success of the anti-HER2 targeted therapy. The gene discussed is ERBB2; the disease is neoplasm.