Impact of tumor infiltrating CD63 positive cells on survival in patients with glioblastoma multiforme

BACKGROUND: Glioblastoma multiforme (GBM) is the most aggressive type of brain cancer in adults. It is suggested that tumour micro-environment might influence treatment outcome. The aim of the study was to evaluate the impact of tumor infiltrating CD63 positive (CD63+) inflammatory and immune cells on treatment response and survival of GBM patients. METHODS: Forty patients were operated and received postoperative radiotherapy (+/- chemotherapy for recurrent disease). In surgically excised GBM tissues, the number of CD63+ cells per microscopic field was determined and correlated with patient's survival. RESULTS: Immunohistochemical parameters were examined by two independent researchers whose results were in good accordance (R=0.8, P<0.001). Median survival time of the study group was 10.0 months (95% CI 9.0-11.0). However, the survival time clearly depended on the number of CD63+ cells in GBM tissue (log rank test, P=0.003). Median survival times for patients with low (<median) and high (>= median) number of CD63+ cells were 9.0 months (95% CI 8.1-9.9) and 12.0 months (95% CI 8.5-15.5) respectively. In multivariate analysis, the number of CD63+ cells emerged as a significant independent predictor for overall survival (HR 2.4, 95% CI 1.2-5.1, P=0.02). CONCLUSIONS: The higher number of tumor infiltrating CD63+ inflammatory and immune cells in GBM tissue corresponded to better survival after postoperative radiotherapy. Since radiotherapy is one of the cornerstones of adjuvant treatment in GBM, further studies are needed for better understanding of GBM biology.