Granzyme B (GB) is a serine protease that is synthesized by activated cytotoxic T-lymphocytes and natural killer cells; it induces apoptosis of neoplastic cells. When expressed in the tumor microenvironment, GB is considered to be a favorable prognostic factor in various types of cancers in humans. A study by Costa, et al published in Oral Oncology evaluated the density of GB cells in 55 patients with oral cavity squamous cell carcinoma (OCSCC) and metastatic and nonmetastatic lymph nodes utilizing immunohistochemistry. The high density of GB cells demonstrated an association with the high percentage of Bax and annexin V neoplastic cells. Further, the number of peritumoral GB cells was significantly higher in the OCSCC group without lymph node metastasis, when compared with the metastatic OCSCC group. OCSCC patients with a high density of peritumoral GB cells demonstrated 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 nonmetastatic lymph nodes than in metastatic lymph nodes. The authors suggest that the increased expression of GB in the tumor microenvironment of OCSCC and in lymph nodes may have a beneficial effect against neoplastic cells, contributing to apoptosis of these cells and increased survival of patients.
Source: Oral Oncology, published online January 11, 2010, via elsevier.com)