Prognostic Value of the Immunohistochemical Detection of Cellular Components of the Tumor Microenvironment in Oral Squamous Cell Carcinoma: A Systematic Review.

This study aims to investigate the prognostic impact of cellular components of the tumor microenvironment (TME), analyzed through immunohistochemistry, in oral squamous cell carcinoma (OSCC). This review was conducted following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Searches were performed in EMBASE, Medline/PubMed, Cochrane Collaboration Library, Web of Science, ScienceDirect, Scopus, and Google Scholar. After applying the study criteria, 59 articles were included, involving the analysis of cancer-associated fibroblasts (CAFs), immune cells, and endothelial cells. It was found that TME rich in α-SMA-positive CAFs, tumor-associated macrophages, and dendritic cells contribute to the invasion and progression of OSCC, resulting in a poorer prognosis. In contrast, the presence of high amounts of NK CD57 cells, CD8/CD45RO T cells, and PNAd endothelial cells are associated with anti-tumor immune responses in OSCC and improved survival rates. CD3 and CD4 T cells, Treg cells, B cells, and mast cells have shown little to no evidence of prognostic utility. Several stromal components of TME were found to have a strong impact on the aggressiveness of OSCC, reaffirming the potential use of these biomarkers as prognostic tools and therapeutic targets.