Up-regulation of miR-335 predicts a favorable prognosis in esophageal squamous cell carcinoma.

[esophageal squamous cell carcinoma]

MicroRNAs (miRNAs ) are noncoding RNAs that regulate multiple cellular processes during cancer progression . MiR-335 has recently been identified to be involved in tumorigenesis of several cancers such as ovarian cancer and gastric cancer . However , the regulation of miR-335 in esophageal squamous cell carcinoma (ESCC ) has not been reported yet .Expression of miR-335 in tumor and their normal matched tissues was determined by quantitative real-time PCR in 67 ESCC patients and its association with overall survival of patients was analyzed by statistical analysis .The expression level of miR-335 was reduced in malignant tissue samples in comparison to normal matched tissue (P < 0 .05 ). It was also proved that miR-335 expression was associated with ESCC histological grade , lymph node metastasis , tumor stage and clinical stage (P < 0 .05 ). In addition , the Kaplan-Meier survival curves revealed that low miR-335 expression was associated with poor prognosis in ESCC patients . Multivariate analysis showed that miR-335 expression was an independent prognostic marker of overall survival of ESCC patients .The study proves for the first time that miR-335 is down regulated in a majority of ESCC patients . Our results indicate that miR-335 expression is an independent prognostic factor for patients with esophageal cancer , which might be a potential valuable biomarker for ESCC .