Clinical significance of high CTC levels in patients with metastatic breast cancer irrespective of location or number of metastatic sites and hormone receptor status or HER2 status of tumour has been confirmed in a large trial in [62] (median PFS 12.0 versus seven months for patients with CTCs <5 and ≥5, respectively; p < 0.001). The gene discussed is ERBB2; the disease is neoplasm.