Molecular Genetics of Oral Cancer

Abstract

Oral squamous cell carcinoma (OSCC) is the most common epithelial malignancy in the oral cavity and constitutes more than 90% of oral malignancies. OSCC is a complex malignancy where environmental factors, viral infections and genetic alterations most likely interact, and thus give rise to the malignant condition. Epidemiological investigations have shown that heavy tobacco smoking, high alcohol consumption and human papilloma virus infection are the major risk factors for OSCC development. These factors interact with specific genes important for normal cellular development and genetic alterations may finally lead to a malignant phenotype. Genetic mutations accumulated over time are needed for an oral cancer to develop and several molecular genetic changes have been associated with the development of OSCC. The most important genetic alterations associated with the condition are tumour suppressor genes, oncogenes, epigenetic changes, genomic instability, mitochondrial mutations, microRNAs and loss of heterozygosity. Key Concepts: Oral cancer is caused by extrinsic and/or intrinsic factors. Loss of heterozygosity is an important event in oral carcinogenesis. Mutated p53 is a common event in OSCC. Telomere length is maintained in some OSCC. mtDNA is involved in OSCC. Epigenetic changes seem to be an early event in oral carcinogenesis. miRNA may be aberrant in OSCC.