***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: BACKGROUND MicroRNAs ( miRNAs ) can be used as prognostic biomarkers in many types of cancer . We aim ed to identify miRNAs that were prognostic in patients with nasopharyngeal carcinoma . METHODS We retrospectively analysed  miRNA expression profiles in 312 paraffin-embedded specimens of nasopharyngeal carcinoma from Sun Yat-sen University Cancer Center ( Guangzhou , China ) and 18 specimens of non-cancer nasopharyngitis . Using an 873 probe microarray , we assessed associations between miRNA signatures and clinical outcome in a r and omly selected 156 sample s ( training set ) and vali date d findings in the remaining 156 sample s ( internal validation set ) . We confirmed the miRNAs signature using quantitative RT-PCR analysis in 156 sample s from a second r and omisation of the 312 sample s , and vali date d the miRNA signature in 153 sample s from the West China Hospital of Sichuan University in Chengdu , China ( independent set ) . We used the Kaplan-Meier method and log-rank tests to estimate correlations of the miRNA signature with disease-free survival ( DFS ) , distant metastasis-free survival ( DMFS ) , and overall survival . FINDINGS 41 miRNAs were differentially expressed between nasopharyngeal carcinoma and non-cancer nasopharyngitis tissues . A signature of five miRNAs , each significantly associated with DFS , was identified in the training set . We calculated a risk score from the signature and classified patients as high risk or low risk . Compared with patients with low-risk scores , patients with high risk scores in the training set had shorter DFS ( hazard ratio [ HR ] 2·73 , 95 % CI 1·46 - 5·11 ; p=0·0019 ) , DMFS ( 3·48 , 1·57 - 7·75 ; p=0·0020 ) , and overall survival ( 2·48 , 1·24 - 4·96 ; p=0·010 ) . We noted equivalent findings in the internal validation set for DFS ( 2·47 , 1·32 - 4·61 ; p=0·0052 ) , DMFS ( 2·28 , 1·09 - 4·80 ; p=0·030 ) , and overall survival ( 2·87 , 1·38 - 5·96 ; p=0·0051 ) and in the independent set for DFS ( 3·16 , 1·65 - 6·04 ; p=0·0011 ) , DMFS ( 2·39 , 1·05 - 5·42 ; p=0·037 ) , and overall survival ( 3·07 , 1·34 - 7·01 ; p=0·0082 ) . The five-miRNA signature was an independent prognostic factor . A combination of this signature and TNM stage had better prognostic value than did TNM stage alone in the training set ( area under receiver operating characteristics 0·68 [ 95 % CI 0·60 - 0·76 ] vs 0·60 [ 0·52 - 0·67 ] ; p=0·013 ) , the internal validation set ( 0·70 [ 0·61 - 0·78 ] vs 0·61 [ 0·54 - 0·68 ] ; p=0·012 ) , and the independent set ( 0·70 [ 0·62 - 0·78 ] vs 0·63 [ 0·56 - 0·69 ] ; p=0·032 ) . INTERPRETATION Identification of patients with the five-miRNA signature might add prognostic value to the TNM staging system and inform treatment decisions for patients at high risk of progression . FUNDING Science Foundation of Chinese Ministry of Health , National Natural Science Foundation of China , Pearl River Scholar Funded Scheme , Guangdong Key Scientific and Technological Innovation Program , Guangdong Natural Science Foundation , Fundamental Research Funds for the Central Universities Recent findings have reported that human serum microRNAs ( miRNAs ) can be used as prognostic biomarkers in various cancers . We aim ed to explore the prognostic value of serum miRNAs in nasopharyngeal carcinoma ( NPC ) patients . The  level of serum miRNA  was retrospectively analyzed in 512 NPC patients recruited between January 2001 and December 2006 . In the discovery stage , a microarray followed by reverse transcription‐quantitative polymerase chain reaction was used to identify differentially altered miRNAs in eight patients with shorter survival and eight patients with longer survival who were well matched by age , sex and clinical stage . The identified serum miRNAs were then vali date d in all 512 sample s , which were r and omly divided into a training set and a validation set . Four serum miRNAs  ( miR‐22 , miR‐572 , miR‐638 and miR‐1234 ) were found to be differentially altered and were used to construct a miRNA signature . Risk scores were calculated to classify the patients into high‐ or low‐risk groups . Patients with high‐risk scores had poorer overall survival [ hazard ratio ( HR ) , 2.54 ; 95 % confidence interval ( CI ) , 1.57–4.12 ; p < 0.001 ] and distant metastasis‐free survival ( HR , 3.28 ; 95 % CI , 1.82–5.94 ; p < 0.001 ) than those with low‐risk scores in the training set ; these results were confirmed in the validation and combined sets . The miRNA signature and TNM stage were independent prognostic factors . The combination of the miRNA signature and TNM stage had a better prognostic value than the TNM stage or miRNA signature alone . The four‐serum miRNA signature may add prognostic value to the TNM staging system and provide information for personalized therapy in NPC Dysregulation of miRNA expression plays an important role in cancer development , and circulating miRNAs are biomarkers of several cancers . We explored whether the miRNAs in plasma could be useful clinical biomarkers for multiple myeloma .  miRNA microarray was conducted to identify elevation of four miRNAs and reduced levels of eight miRNAs in the plasma of nine multiple myeloma patients and seven healthy controls . Increased miR-483 - 5p levels and decreased miR-20a were further vali date d in the plasma of 40 myeloma patients and 20 healthy controls using TaqMan quantitative real-time PCR . Receiver operating characteristic ( ROC ) analysis revealed that miR-483 - 5p and miR-20a had considerable diagnostic accuracy , yielding the areas under the ROC curve of 0.745 ( sensitivity 58 % , specificity 90 % ) and 0.74 ( sensitivity 63 % , specificity 85 % ) , respectively . Plasma levels of miR-483 - 5p were associated with ISS staging . Within 14 months of diagnosis , the median progression-free survival of patients with high levels of plasma miR-483 - 5p was 15 months , in comparison with 21 months for patients with low levels of plasma miR-483 - 5p ( p = 0.025 ) . However , miR-20a levels were not correlated with progression-free survival ( p > 0.05 ) . miR-483 - 5p has the potential to be a predictor of myeloma survival 
    Output:
    
Conclusion To our knowledge , this is the first comprehensive systematic review and meta- analysis that examines the prognostic role of circulating miRNAs from blood in head and neck cancer patients .
The combined effect estimates a HR across multiple studies and also supports the previous individual findings that an alteration in miRNA expression is highly associated with poor prognosis .