Prognostic value of immunoexpression of the chemoresistance-related proteins in ependymomas: an analysis of 76 cases

Intracranial ependymomas are the third most common primary brain tumor in c hildren. A variety of chemotherapy protocols have been introduced for the t reatment of ependymoma although overall these have not contributed to patie nts outcome. To our knowledge, data on the prognostic value of immunoexpres sion of the chemoresistance-related proteins (ChRPs) in ependymomas are abs ent. Seventy-six patients with intracranial ependymomas who received combin ed treatment were studied retrospectively. Tumor specimens were immunohisto chemically examined with antibodies to metallothioneins (MT), glutathione S -transferase pi (GST pi) and P-glycoprotein (P-GP). The results demonstrate d significant preponderance of expression of all the above-mentioned ChRPs for the low-grade tumors. The progression-free survival time was found to b e significantly shorter for immunonegative tumors in both tumor grades. Mul tivariate analysis using a Cox hazard model revealed that recurrence-free s urvival time is significantly associated with tumor grade, and MT and P-GP expression. Risk of recurrence increased for the high-grade ependymomas (ha zard ratio 2.85; P = 0.004), and decreased for the MT-positive tumors (haza rd ratio -2.72; P = 0.005) and for the P-GP-positive tumors (hazard ratio - 2.02; P = 0.02). The obtained results allow one to conclude that ChRPs expr ession is closely associated with low-grade ependymomas and immunohistochem ical findings may be estimated as a predictor for local tumor progression.