Source:https://benthamscience.com/ Jun 29 2018Cancers control immune systems and evade immune detection using mediators consisting of immune checkpoint molecules and cellular systems associated with immune suppression.In this review, the complexity of immune-suppressive mechanisms in the tumor milieu of cancers, including oral malignancy is discussed in relation to immune check point inhibitors, regulatory T cells (Treg), myeloid-derived suppressor cells (MDSCs) and cancer-associated fibroblasts (CAFs). In addition, the therapeutic approach of oral pre-cancerous disorders is mentioned. Some reports also advocate that the immunosuppressive efficacy of the oral squamous cell carcinoma (OSCC) milieu is developed in a stepwise manner depending on the stages of OSCCs. Namely, in the early stage, CAFs could be a unique effector; humoral factor(s) from OSCC cells force CAF to exert immune suppression via the direct cell contacts to effector T cells. Potentiated CAF could also affect other immune-suppressive mediators such as Treg, tumor-associated macrophages (TAMs) and MDSCs. In the advanced stage of OSCC, MDSCs could possibly be a major conductor of immune-suppression. However, how OSCCs differentially utilize the immune modulatory aspects involving CAFs, MDSCs and several other factors is not fully understood. Further elucidation of the regulatory pathways structured by tumor-host interactions could identify important therapeutic targets in OSCC development.