The clinicopathological significance of the expression of Granzyme B in oral squamous cell carcinoma

Granzyme B (GB) is a serine protease synthesized by activated cytotoxic T-lymphocytes and natural killer cells that induces neoplastic cells apoptosis. The expression of GB in the tumor microenvironment has been considered a favorable prognostic factor in several types of human cancers. Thus, the aim of this study was to evaluate the density of GB+ cells in samples of oral cavity squamous cell carcinoma (OCSCC), as well as their relationship with clinical and microscopic parameters. GB expression was analyzed in 55 cases of OCSCC and metastatic and non-metastatic lymph nodes by means of immunohistochemistry. The high density of GB+ cells demonstrated an association with the high percentage of Bax+ and annexin V+ neoplastic cells. In addition, the number of peritumoral GB+ cells was significantly higher in the OCSCC group without lymph node metastasis, when compared with the metastatic OCSCC group. Moreover, patients with OCSCC with a high density of peritumoral GB+ cells showed a longer survival time when compared with patients with a lower density of these cells. In lymph node tissues, the density of GB+ cells was significantly higher in non-metastatic lymph nodes than in metastatic lymph nodes. Our findings suggest that the increased of expression of GB in the tumor microenvironment of OCSCC and in lymph nodes may have beneficial effect against neoplastic cells, contributing to apoptosis of these cells and increased survival of patients.