***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Prognostic markers help to stratify patients for treatment by identifying patients with different risks of outcome ( e.g. recurrence of disease ) , and are important tools in the management of cancer and many other diseases . Systematic review and meta-analytical approaches to identifying the most valuable prognostic markers are needed because ( sometimes conflicting ) evidence relating to markers is often published across a number of studies . To investigate the practicality of this approach , an empirical investigation of a systematic review of  tumour markers for neuroblastoma was performed ; 260 studies of prognostic markers were identified , which considered 130 different markers . The reporting of these studies was often inadequate , in terms of both statistical analysis and presentation , and there was considerable heterogeneity for many important clinical /statistical factors . These problems restricted both the extraction of data and the meta- analysis of results from the primary studies , limiting feasibility of the evidence -based approach . Guidelines for reporting the results of primary prognostic marker studies in cancer , and other diseases , are given in order to facilitate both the interpretation of individual studies and the undertaking of systematic review s , meta- analysis and , ultimately , evidence -based practice . General availability of full individual patient data is a necessary step forward and would overcome the majority of problems encountered , including poorly reported summary statistics and variability in cutoff level , outcome assessed and adjustment factors used . It would also limit the problem of reporting bias , although publication bias will remain a concern until studies are prospect ively registered . Such changes in practice would help important evidence -based review s to be conducted in order to establish the most appropriate prognostic markers for clinical use , which should ultimately improve patient care PURPOSE Pediatric intracranial ependymomas are a heterogeneous group of neoplasms with unpredictable clinical and biologic behavior . As part of ongoing studies to identify potential biologic and therapeutic markers , we analyzed the role of human telomere reverse transcriptase ( hTERT ; the catalytic subunit of telomerase ) expression as a prognostic marker for this disease . PATIENTS AND METHODS Primary intracranial ependymomas that were resected at our institution between 1986 and 2004 were identified through the pathology and oncology data bases . A tissue array was constructed from the patient sample s and hTERT expression was evaluated by immunohistochemistry . Twenty-one sample s were also analyzed for  telomerase activity ( telomerase repeat amplification protocol assay ) . RESULTS Eighty-seven tumors from 65 patients were analyzed .  Five-year progression-free survival was 57 % ( SEM , 12 % ) and 21 % ( SEM , 8 % ) for hTERT-negative and hTERT-positive tumors , respectively ( P = .002 ) . Five-year overall survival was 84 % ( SEM , 7 % ) and 41 % ( SEM , 7 % ) for hTERT-negative and hTERT-positive tumors , respectively ( P = .001 ) . There was good correlation between telomerase activity and hTERT expression ( kappa = 0.637 ) . Multivariate analysis revealed hTERT expression to be the single most important predictor of survival of all known pathologic , clinical , and treatment factors ( hazard ratio , 60.4 ; 95 % CI , 6.4 to 561 ) . All four patients with hTERT-negative tumors at relapse are still alive , with median follow-up of 11.2 years . CONCLUSION In this study , hTERT expression was the strongest predictor of outcome and was independent of other clinical and pathologic prognostic markers . It represents a simple and reliable biologic prognostic factor for intracranial ependymomas . These results should be confirmed in larger prospect i ve trials OBJECT Ependymomas in children continue to generate controversy regarding their histological diagnosis and grading . optimal management , and possible prognostic factors . To increase our knowledge of these tumors the authors addressed these issues in a cohort of children with prospect ively staged ependymomas treated with radiotherapy and chemotherapy .  METHODS Children between the ages of 2 and 17.3 years harboring an intracranial ependymoma confirmed by a central review of the tumor 's pathological characteristics were treated according to Children 's Cancer Group Protocol 921 from 1986 to 1992 . Treatment following surgery and postoperative tumor staging ( including brain computerized tomography or magnetic resonance [ MR ] imaging , spinal MR imaging or myelography , and cerebrospinal fluid cytological investigation ) included craniospinal irradiation with a local boost to the primary tumor and patient r and omization to receive adjuvant chemotherapy with either 1 ) CCNU , vincristine , and prednisone , or 2 ) the eight-drugs-in-1-day regimen . Central ized review of the tumor pathological characteristics revealed 20 ependymomas and 12 anaplastic ependymomas in the 32 children included in the study . Diagnoses made at the individual institutions included anaplastic ( malignant ) ependymoma ( 15 patients ) , ependymoma ( four patients ) , ependymoblastoma ( nine patients ) , ependymoastrocytoma ( one patient ) , and primitive neuroectodermal tumor ( three patients ) , which were discordant with the central ized review diagnosis in 22 of 32 cases . Only three of the 32 patients had metastatic disease ( two with M and one with M3 stages ) . At surgery , 47 % of tumors were estimated to be totally resected . Among the 14 of 17 patients who suffered a relapse and were evaluated for site of relapse , 10 ( 71 % ) had an isolated local relapse , three ( 21 % ) had concurrent local and metastatic relapse , and only one ( 7 % ) had an isolated metastatic relapse . Kaplan-Meier estimates of 5-year progression-free survival ( PFS ) and overall survival rates were 50 + /- 10 % and 64 + /- 9 % , respectively . CONCLUSIONS Predictors of PFS duration included an estimate of the extent of resection made at surgery ( total compared with less than total , p = 0.0001 ) and the amount of residual tumor on postoperative imaging as verified by central ized radiological review ( < or = 1.5 cm2 compared with > 1.5 cm2 , p < 0.0001 ) . No other factors , including central ly review ed tumor histopathological type , location , metastasis and tumor ( M and T ) stages , patient age , race , gender , or chemotherapy treatment regimen significantly correlated with PFS duration . The pattern of predominantly local relapse and the important influence of residual tumor or the extent of resection on PFS duration confirms a prevailing impression that local disease control is the major factor in the prediction of outcome of ependymoma . Survival rates were comparable with those reported by other investigators who have treated patients with similar doses of radiation and no chemotherapy 
    Output:
    
Although the prognostic impact of MIB-1 immunoexpression in IE could be confirmed , there remains lack of further reliable IPM that could be used in routine diagnosis .