Genetic and Epigenetic Biomarkers of Molecular Alterations in Oral Carcinogenesis

Worldwide, oral cancers represent the 6th most common type of cancer. Oral squamous cell carcinoma (OSCC), which is the most common type of oral cancer, is present in about 90% of the patients with this malignancy. OSCC presents a survival rate up to 80%, if it is detected in an early stage (T1), but if detected at later stages (T3 - T4) the survival rate decreases to 20 - 30%. Due to these survival rates, it is obvious that there is an urgent need to introduce new molecular biomarkers for the early, noninvasive diagnosis of oral cancers from saliva. These biomarkers will aid in increasing the survival rate of the patients for the long-term. MicroRNAs are part of a class of small, non-coding RNAs that contain 19 - 23 nucleotides. MicroRNAs play an important role in the regulation of biochemical mechanisms, cell proliferation, and other cellular mechanisms in the human body. Recently, due to the developments in the field of molecular genetics, salivary microRNAs became important biomarkers in early detection and monitoring of oral cancers by noninvasive methods. We want to present in this review the most important genetic and epigenetic biomarkers involved in oral carcinogenesis, focusing especially on the salivary microRNAs as biomarkers in early diagnosis of OSCC.