High expression levels of erythropoietin and its receptor are not correlated with shorter survival in human glioblastoma.

Erythropoietin (EPO) is used to treat anemia in neoplastic disease. EPO also exerts neuroprotective effects on neuronal cells, making a prophylactic use against the neurocognitive effects of radiochemotherapy probable. However, EPO/EPO-receptor (EPOR) signalling has been also detected in glioblastoma cells. Data collected in vitro and in vivo show conflicting results on the effect of EPO on malignant gliomas. The association between EPO and EPOR expression and the prognosis of human glioblastomas was analyzed. Probes of human glioblastomas with complete documentation of clinical course and treatment were assessed by immunohistochemistry for the expression of EPO and EPOR (n=80). Using univariate and multivariate survival analysis, the association with age, gender, radiation, chemotherapy and extent of resection was determined. High levels of EPOR were correlated with a median survival advantage of 7 months (p<0.01). By univariate, but not multivariate, analysis, high levels of EPO and EPOR were associated with a significant prolongation of 7 months median survival when compared to low levels of both molecules. In patients treated with radiochemotherapy adjuvant to surgery, the median survival was 6.5 months longer in patients with high levels of EPOR (p<0.04). According to previous studies, longer patient survival is associated with EPOR expression. Therefore, EPO appears to be safe for the treatment of anemia in glioblastoma patients. However, a prophylactic use, i.e., for neuroprotection, is not recommended in light of the functional studies described in the literature.