Chronic Inflammatory Mediators Induced Malignant Changes in Inflammatory Microenvironment of Oral Potentialy Malignant Conditions - An Emerging Concept

Abstract

Potentially malignant conditions of the oral cavity are potential threat to mankind because of its malignant changes later. Oral potentially malignant conditions are chronic inflammatory mucocutaneous disorder affecting oral mucosa. Inflammatory mediators induced by chronic inflammatory microenvironment of premalignant conditions are cytokines, chemokines, growth factors, proteolytic enzymes, released by inflammatory cells such as macrophages, lymphocytes, neutrophils, mast cells, activate transcriptional factors such as NF-kB, STAT-3 and HIF-1, promotes cell proliferation, angiogenesis, tumor promotion, resistant to apoptosis, epithelial to mesenchymal transition, induced invasion and metastasis. Carcinoma associated fibroblasts in tumor microenvironment originated by activated fibroblasts secretes cytokines and growth factors promotes tumor progression by cell proliferation, angiogenesis, cell survival, genomic instability, invasion and metastasis. Myeloid derived suppressor cells are specialized heterogeneous immature myeloid progenitor cells that are dendritic cells, macrophages, granulocytes produced upon chronic inflammatory mediators. These cells responsible for immune evasion, immunosuppression and tumor progression by various mechanisms and interaction with other immune cells, activating transcriptional factors such as NF-kB and STAT-3. This article describe about roles of chronic inflammatory cells and their mediators in inflammatory microenvironment of premalignant conditions bring about malignant changes in oral sub mucous fibrosis and oral lichen planus.