Recently, it was found that pomolic acid suppresses HER2 and CXCR4 expression in HER2-positive breast cancer cells through ERK pathway and NF-κB inactivation [51] and CXCR4 inhibitors efficiently reduces tumor growth and metastasis in both Herceptin-sensitive and Herceptin-resistant HER2 patient-derived xenografts thus CXCR4 being considered a very promising therapeutic target in patients with HER2-overexpressing breast cancer [16]. This evidence concerns the gene CXCR4 and breast cancer.