clinicaltrials.gov Identifier: NCT00916409.

Chemotherapy in glioma is poorly effective: the blood-brain barrier and intrinsic and/or acquired drug resistance of tumor cells could partly explain this lack of major effect. We investigated expression of P-glycoprotein (Pgp), multidrug resistance protein (MRP) 1, MRP3, MRP5 and glutathione-S-transferase pi (GST-pi) in malignant glioma patients. Cytofluorimetric analysis of 48 glioma specimens and 21 primary cultures showed high levels of MRP1, moderate levels of MRP5 and low levels of Pgp, GST-pi and MRP3. Immunohistochemistry (25 glioma specimens) showed expression of GST-pi (66.7% of cases), MRP1 (51.3%), MRP5 (45.8%), Pgp (34.8%) and MRP3 (29.9%) in tumor cells. Moreover, analysis of tumor samples by real time quantitative PCR showed mRNA expression of all investigated genes. Tumor vasculature, analyzed in glioma specimens and in tumor derived endothelial cells, showed expression of all investigated proteins. Non-tumor brain samples (from a patient with arteriovenous malformation and from one with epilepsy), normal human astrocytes and cultured endothelial cells were also analyzed: astrocytes and endothelial cells expressed the highest levels of the investigated proteins, mainly MRP1 and MRP5. No significant differences in proteins expression were detected between primary or recurrent gliomas, suggesting that glioma chemoresistance is mostly intrinsic. Therefore, we detected, for the first time, the presence of MRP3 and MRP5 on glioma specimens--both in tumor and endothelial cells--and we delineated an expression profile of chemoresistance proteins in glioma. The possible association of inhibitors of drug efflux pumps with chemotherapy could be investigated to improve drugs delivery into the tumor and their cytotoxic effects.

Human tumors can constitutively express cytokines and growth factors, but the extent of this expression has not been investigated. Using 44 different probes to cytokines, growth factors, and their receptors, we tested 21 melanoma and 5 melanocyte cultures for RNA transcript expression by reverse transcriptase-polymerase chain reaction. With 30 amplification cycles, expression of the cytokines interleukin (IL)-1 beta, IL-6, leukemia inhibitory factor (LIF), IL-7, gro alpha, IL-8 and the p35 chain of IL-12 was detected in more than 60% of melanomas. Concomitant receptors for IL-6 and IL-7 were also detected. IL-1 alpha, IL-5, Rantes, IL-10, interferon (IFN)-beta, tumor-necrosis factor (TNF)-alpha, G-colony-stimulating factor (CSF) and GM-CSF were expressed at lower levels. Melanocytes showed greatly reduced cytokine RNA transcripts, and only gro alpha was consistently detected. No expression of IL-2, IL-3, IL-4, IL-9, the p40 chain of IL-12, IFN-alpha or IFN-gamma RNA transcripts was detected in melanomas or melanocytes. The growth factors expressed by melanomas and, after further signal amplification, by melanocytes were transforming growth factor (TGF)-alpha, epidermal growth factor (EGF), TGF-beta, endothelial-cell growth factor (ECGF), basic-fibroblast growth factor (bFGF), nerve growth factor (NGF) and steel. The receptors EGFR, FGFR, NGFRp70 and c-kit were also expressed by melanomas and melanocytes. These results point to new possible autocrine and paracrine pathways in melanoma biology.

Purpose: Recent data suggest that methylation of the DNA repair gene O 6 -methylguanine DNA methyltransferase (MGMT), by increasing the chemosensitivity of glioblastoma multiforme, is significantly associated with improved prognosis. Results in contradiction with these findings, however, are present in the literature and the clinical and genetic context framing MGMT methylation is poorly characterized. Experimental Design: To address these issues, we have investigated the MGMT methylation status, clinical and magnetic resonance imaging characteristics, and relevant genetic features (loss of heterozygosity on17p and19q, EGFR amplification, and p53 mutations) in a retrospective study on 86 patients affected by glioblastoma multiforme: 72 patients had a clinical history indicating de novo insurgence of the tumor and the remaining 14 were secondary glioblastoma multiforme. Results: MGMT methylation was detected by methylation-specific PCR in 41 of 86 cases (47.7%; Meth+). Progression-free survival and overall survival were significantly longer in Meth+ than in Meth-patients [10 versus 7 months (P = 0.003, log-rank test) and 18 versus 14 months (P = 0.0003, log-rank test), respectively]. Mixed-nodular enhancement at magnetic resonance imaging was significantly more frequent in Meth+ and secondary glioblastoma multiforme and ring enhancement in Meth-and primary glioblastoma multiforme (P < 0.005). MGMT methylation was more present in secondary glioblastoma multiforme (P = 0.006) and associated with loss of heterozygosity on 17p and/or 19q (P = 0.005). Conclusions: These observations suggest that MGMT methylation is part of a genetic signature of glioblastomas that developed from lower-grade gliomas.

This study provides Class II evidence that vitamin E supplementation significantly reduces the relative risk of developing signs or symptoms of neurotoxicity (relative risk = 0.14) (95% confidence interval = 0.02-1.00, p < 0.05).