Very recently, it was also found that CXCR4 could be a very promising therapeutic target in patients with HER2-overexpressing breast cancer patients, since CXCR4 inhibitors efficiently reduced tumor growth and metastasis in both Herceptin-sensitive and Herceptin-resistant HER2 patient-derived xenografts [33]. The gene discussed is CXCR4; the disease is neoplasm.