LOXL4 and breast cancer: LOXL4 mRNA was expressed in MDA-MB-231 highly invasive breast cancer cells, but not in poorly invasive and non-metastatic breast cancer cells MCF7 and T47D [53]. LOXL4 was over-expressed in most invasive HNSSC primary or metastatic tumors and cell lines, primary tumors of oral cavity as well as thyroid gland whereas no expression was detected in normal epithelial cells [54].