ERBB4 and lip and oral cavity carcinoma: The analysis of the tyrosine kinase erbB family receptors (erbB1/EGFR, erbB2/Neu/HER2, erbB3/HER3, and erbB4/HER4) had indicated their participation in embryogenesis, proliferation, differentiation, and malignant transformation of breast, renal, colon, and oral cancer.