The Role of the Microenvironment in Oral Diseases

Oral cancer is the sixth most common cancer in the world. Tongue squamous cell carcinoma (SCC) is highly aggressive, and almost half of the patients still die of the disease. Tongue SCC lacks reliable markers for disease recovery and progression. It is becoming increasingly evident that in addition to the carcinoma cells, the other cell types in the cancer microenvironment are critically important for the tumor development and could be potential targets for therapy. The microenvironment consists of fibroblasts, endothelial and immune cells as well as extracellular matrix produced by the cells. Particularly cancer-associated fibroblasts seem to be prominent modifiers of cancer progression. It has not yet been demonstrated where cancer-associated fibroblasts come from in oral SCCs. The mechanisms how they participate in cancer growth and invasion process is also largely not known. The role of stem cells in oral carcinomas is another goal. Both fibroblasts and stem cells have been implicated in epithelial-to-mesenchymal transformation.

The matrix metalloproteinases (MMPs) are a family of enzymes modulating a wide range of proteins including almost all extracellular matrix components, cytokines, growth factors and other biological signalling molecules. They participate in tissue remodelling as well as in cellular migration, adhesion, proliferation and apoptosis. MMPs are known be increased in a variety of diseases, including oral mucosal diseases and cancer. The exact role of MMPs in oral diseases is mostly unknown. Due to the increased level and activity of MMPs in several occasions, many MMP inhibitors have been developed for clinical use. Inhibiting MMP synthesis and activity has been subject to extensive research for the past decades. However, recently it has been found that some MMPs might also play a protective role, e.g. in cancer. Therefore more work needs to be done to elucidate the role and importance of MMP activation and inhibition in various stages of oral carcinoma and other oral diseases.

Group leader: Professor Tuula Salo
Phone (08) 537 5592, email: tuula.salo(at)oulu.fi