Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
Q: Context: In order to improve the survival of patients with a glioblastoma multiforme tumor (GBM), new therapeutic strategies must be developed. The use of a death inducing ligand such as TRAIL (TNF Related Apoptosis Inducing Ligand) seems a promising innovative therapy. The aim of this study was to quantify the expression of the death regulating receptors TRAIL-R1, TRAIL-R2 and TRAIL on primary GBM specimens and to correlate this expression with survival.', 'Expression of TRAIL and TRAIL-receptors was assessed by immunohistochemistry, both quantitatively (% of positive tumor cells) and semi-quantitatively (staining intensity) within both the perinecrotic and intermediate tumor zones of primary GBM specimens. RT-PCR of GBM tissue was performed to show expression of TRAIL receptor mRNA.', 'Immunohistochemistry showed a slight diffuse intracytoplasmic and a stronger membranous staining for TRAIL and TRAIL receptors in tumor cells. Semi-quantitative expression of TRAIL showed a significantly higher expression of TRAIL in the perinecrotic zone than in the intermediate zone of the tumor (P=0.0001). TRAIL-R2 expression was significantly higher expressed than TRAIL-R1 (P=0.005). The antigenic load of TRAIL-R2 was positively correlated with survival (P=0.02). Multivariate analysis of TRAIL-R1 within the study group (n=62) showed that age, gender, staining intensity, antigenic load, % of TRAIL-R1 expression, were not statistically correlated with survival however radiotherapy was significantly correlated (multivariate analysis: age: P=0.15; gender: P=0.64; staining intensity: P=0.17; antigenic load: P=0.056; % of TRAIL-R1 expression: P=0.058; radiotherapy: P=0.0001). Subgroup analysis of patients who had received radiotherapy (n=47) showed a significant association of % of TRAIL-R1 expression and the antigenic load of TRAIL-R1 with survival (multivariate analysis: P=0.036, respectively, P=0.023). Multivariate analysis of TRAIL-R2 staining intensity and antigenic load, within the study group (P=0.004, respectively, P=0.03) and the subgroup (P=0.002, respectively, P=0.004), showed a significant association with survival. RT-PCR analysis detected a negative relation between the amount of TRAIL-R1 mRNA and the WHO grade of astrocytic tumors (P=0.03).
Answer: TRAIL-R1 and TRAIL-R2 expression on tumor cells are independent prognostic factors for survival in patients with a glioblastoma multiforme. Both receptors could be targets for TRAIL therapy. As TRAIL-R2 is more expressed, in comparison with TRAIL-R1, on GBM tumor cells, TRAIL-R2 seems to be of more importance as a target for future TRAIL therapy than TRAIL-R1.
A:
Is tRAIL-receptor expression an independent prognostic factor for survival in patients with a primary glioblastoma multiforme?