***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: Summary The relationship of immunohistochemical indices of proliferating cell nuclear antigen ( PCNA ) and Ki-67 to local control and survival rates for patients with oesophageal squamous cell carcinomas treated by definitive radiotherapy ( RT )  was investigated . Biopsy material s before RT were obtained from 65 patients with oesophageal cancer . The median PCNA labelling index ( LI ) and the median Ki-67 LI were 52 % and 45 % respectively . The PCNA LI was independent of known prognostic factors on local control for oesophageal cancer , although Ki-67 LI correlated with several prognostic factors . In the univariate analysis , patients with the PCNA LI of < 52 % or the Ki-67 LI of < 45 % showed significantly higher local recurrence rates than those with higher LIs ( both P < 0.05 ) . This difference in local control rate according to LIs was prominent for the patients treated with conventional fractionation . In the multivariate analysis , T-stage ( P = 0.0056 ) and PCNA LI ( P = 0.0332 ) were significant factors for local control in the final model using a stepwise regression procedure . In conclusion , PCNA LI and Ki-67 LI were significantly correlated with local control probabilities in oesophageal squamous cell carcinomas treated by definitive RT Background Mortality is high in patients with esophageal carcinoma as tumors are rarely detected before the disease has progressed to an advanced stage . Here , we sought to isolate cell-free DNA released into the plasma of patients with esophageal carcinoma , to analyze copy number variations of marker genes in the search for early detection of tumor progression . Methods  Plasma of 41 patients with esophageal carcinoma was prospect ively collected before tumor resection and chemotherapy .  Our data set result ed heterogeneous for clinical data , resembling the characteristics of the tumor . DNA from the plasma was extracted to analyze copy number variations of the erbB2 gene using real-time PCR assays . Results The real-time PCR assays for erbB2 gene showed significant ( P = 0.001 ) copy number variations in the plasma of patients with esophageal carcinoma , as compared to healthy controls with high sensitivity ( 80 % ) and specificity ( 95 % ) . These variations in erbB2 were negatively correlated to the progression free survival of these patients ( P = 0.03 ) , and revealed a further risk category stratification of patients with low VEGF expression levels . Conclusion The copy number variation of erbB2 gene from plasma can be used as prognostic marker for early detection of patients at risk of worse clinical outcome in esophageal cancer The present study retrospectively examines the correlation between the outcome of patients with locally advanced esophageal squamous cell carcinoma ( LAEC ) after multimodal treatment ( radiochemotherapy + /- surgery )  and the expression of apoptosis-regulating proteins in pretherapeutic biopsies . Thirty-eight patients with LAEC who took part in a prospect i ve multicentric trial received radiochemotherapy , optionally followed by surgery .  Pretreatment tumor biopsies were immunohistochemically investigated for expression of p53 , Bcl-2 , Bax ( bcl-2-associated X protein ) , and Bcl-X(L ) ( bcl-2-related X protein ) . The overall expression of p53 , Bcl-2 , Bax , and Bcl-X(L ) was 52.6 , 57.9 , 100 , and 97.4 % respectively . Tumors without p53 expression and tumors with weak Bcl-X(L ) expression showed response to chemotherapy more frequently ( 55.6 and 52.6 % , respectively ) than tumors positive for p53 expression and tumors with strong Bcl-X(L ) expression ( 30.0 and 31.6 % , respectively ) ; however , these differences did not attain statistical significance . No correlations were found between the expression of Bcl-2 and Bax and the response to chemotherapy .  In patients treated by  radiochemotherapy and  surgery , p53-negative tumors showed a significantly better outcome than p53-positive tumors ( mean survival , 31.1 months versus 11.3 months ; P = 0.0378 ) . Additionally , a more favorable outcome was observed in tumors positive for Bcl-2 ( not significant ) , whereas no differences in survival were observed in relation to the expression of Bax or Bcl-X(L ) . No differences in survival were observed in patients treated by radiochemotherapy without subsequent resection therapy in relation to the expression of apoptosis-regulating proteins . Immunohistochemical examination of pretherapeutic tumor biopsies for expression of apoptosis-regulating proteins may help to identify patients with LAEC who may benefit from multimodal treatment and those who may not PURPOSE The prognosis and the radiosensitivity of macroscopically infiltrative type of esophageal carcinoma are worse than those of the localized type of esophageal carcinoma treated with irradiation . The aim of this study was to investigate the cause of differences in radiosensitivity and prognosis of esophageal carcinoma according to macroscopic type from the viewpoint of tumor angiogenesis . METHODS AND MATERIAL S A total of 40 surgically resected esophageal carcinoma tissues with good material remaining were selected at r and om from macroscopically localized type ( n = 20 ) and infiltrative type ( n = 20 ) of esophageal carcinoma . The highest intratumoral microvascular density ( h-MVD ) , average intratumoral microvascular density ( a-MVD ) , Ki67 labeling index , and expression of vascular endothelial growth factor ( VEGF ) in each section were estimated . RESULTS h-MVD was significantly ( p = 0.0006 ) greater in the infiltrative type than in the localized type , whereas a-MVD ( p = 0.0014 ) and Ki67 labeling index ( p = 0.022 ) were significantly lower in the infiltrative type than in the localized type . The expression level of VEGF was significantly ( p < 0.0001 ) higher in the infiltrative type . CONCLUSIONS The generally underdeveloped vascular densities with low proliferation activities ( suggesting increase of hypoxic fraction ) seemed to be one of the reasons for unfavorable radiosensitivities of infiltrative type of esophageal carcinoma . The infiltrative type of esophageal carcinoma shows a high level of VEGF expression and high activity of tumor angiogenesis . The locally enhanced neovascularization , which occurs frequently in hematogenous metastasis seemed to be one of the reasons for the unfavorable prognosis of the infiltrative type of esophageal carcinoma Long-term beta blockade for perhaps a year or so following discharge after an MI is now of proven value , and for many such patients mortality reductions of about 25 % can be achieved . No important differences are clearly apparent among the benefits of different beta blockers , although some are more convenient than others ( or have slightly fewer side effects ) , and it appears that those with appreciable intrinsic sympathomimetic activity may confer less benefit . If monitored , the side effects of long-term therapy are not a major problem , as when they occur they are easily reversible by changing the beta blocker or by discontinuation of treatment . By contrast , although very early IV short-term beta blockade can definitely limit infa rct size , more reliable information about the effects of such treatment on mortality will not be available until a large trial ( ISIS ) reports later this year , with data on some thous and s of patients entered within less than 4 hours of the onset of pain . Our aim has been not only to review the 65-odd r and omized beta blocker trials but also to demonstrate that when many r and omized trials have all applied one general approach to treatment , it is often not appropriate to base inference on individual trial results . Although there will usually be important differences from one trial to another ( in eligibility , treatment , end-point assessment , and so on ) , physicians who wish to decide whether to adopt a particular treatment policy should try to make their decision in the light of an overview of all these related r and omized trials and not just a few particular trial results . Although most trials are too small to be individually reliable , this defect of size may be rectified by an overview of many trials , as long as appropriate statistical methods are used . Fortunately , robust statistical methods exist -- based on direct , unweighted summation of one O-E value from each trial -- that are simple for physicians to use and underst and yet provide full statistical sensitivity . These methods allow combination of information from different trials while avoiding the unjustified direct comparison of patients in one trial with patients in another . ( Moreover , they can be extended of such data that there is no real need for the introduction of any more complex statistical methods that might be more difficult for physicians to trust . ) Their robustness , sensitivity , and avoidance of unnecessary complexity make these particular methods an important tool in trial overviews 
    Output:
    
Data collected were not sufficient to determine the prognostic value of VEGF in patients with esophageal adenocarcinoma .
CONCLUSIONS In this meta- analysis , elevated VEGF expression was associated with poor survival in patients with esophageal cancer but not esophageal adenocarcinoma .