ERBB4 and head and neck squamous cell carcinoma: The human epithelial GFR family, including EGFR, Her2, Her3 and Her4, has been found to play an essential role in tumor growth, migration, survival, metastasis, adhesion and angiogenesis not only in HNSCC but also in glioblastoma, lung, breast, gastric and colorectal cancers [39].