Viral and molecular aspects of oral cancer.

Squamous cell carcinoma (SCC) is the most common epithelial malignancy in the oral cavity. SCCs and their variants constitute over 90% of oral malignancies, and the disease is associated with poor prognosis. OSCC is a complex malignancy where environmental factors, virus infections, and genetic alterations most likely interact, and thus give rise to the malignant condition. Herein, we review the available literature regarding high-risk factors such as alcohol and tobacco usage; discuss the roles of human papillomaviruses (HPV), the Epstein-Barr virus, and the human herpes simplex virus (HSV); and evaluate several candidate genes associated with the condition: p53, p16(INK4) and p21(WAF1/CIPI), survivin, B-cell lymphoma-2 (BCL-2), keratins, Fibroblast growth factor 3 (FGF3), FGF4, FGF19, Oral cancer overexpressed gene 1 (ORAOV1), and Cyclin D1 (CCND1).