Prognostic significance of immunohistochemical biomarkers in oral squamous cell carcinoma

Advances in understanding of the molecular mechanisms underlying oral squamous cell carcinoma (OSCC) have resulted in an increasing number of biomarkers that can be used to predict the behaviour of this disease. The authors conducted a literature review of studies examining the role of immunohistochemistry-based protein biomarkers in predicting OSCC outcome. Only articles published in PubMed-indexed journals over the past 5 years were considered. 22 molecular biomarkers were identified and classified into five groups based on their biological functions: cell cycle acceleration and proliferation; tumour suppression and apoptosis; hypoxia; angiogenesis; and cell adhesion and matrix degradation. The cell cycle acceleration and proliferation biomarkers showed the most divergent prognostic findings. Studies on tumour suppression and apoptosis biomarkers were the most prevalent. There were only a few studies examining molecular biomarkers of hypoxia and angiogenesis, and studies examining cell adhesion and matrix degradation biomarkers have shown that this group has the greatest potential for assessing prognostic parameters. Amongst the several proteins analysed, the immunohistochemical expression levels of epithelial growth factor receptor (EGER), p53, and matrix metalloproteinases (MMPs) have demonstrated the greatest potential for survival prediction in OSCC, but this review demonstrates that their prognostic relevance is debatable and requires further standardisation.