TUMOR SUPPRESSION IN ONCOGENESIS OF ORAL SQUAMOUS CELL CARCINOMA

Oral cancer is relatively uncommon in the industrialized world but accounts for about 5% of all cancer deaths worldwide, and up to 40% of all malignancies in South and South-East Asia. The present paper aims to review the role and signifivance of tumor suppressor genes in the genetic and molecular pathways to oral squamous cell carcinoma (SCC), which is the most common form of oral cancer and frequently associated with poor prognosis. The high incidence of SCC in betel quid users is due to the severe chemical insult resulting in multiple alterations of oncogenes and tumor suppressing genes. Of the latter, SCC in betel quid users is more often associated with alterations in P16 and pRb (typically at least 60% of the cases) than in p53 (typically less than 20%). However, in most parts of the world SCC is mostly attributed to smoked tobacco and alcohol, which inflict a synergistic effect when used in combination. The characteristic prevalent alterations are common (50 to 100%) in the tumor suppressor gene p53. Potential applications of the genes, corresponding expressed proteins and related other markers are discussed in brief.