[Serum miRNAs as new biomarkers for esophageal squamous cell carcinoma]

Esophageal squamous cell carcinoma (ESCC) is one of the most common types of malignancies in China. Most ESCC patients are diagnosed at middle to late stages with poor prognosis due to the lack of an effective method for early diagnosis. MicroRNAs (miRNAs) are a family of endogenous small non-coding RNAs that can regulate ESCC development and progression by repressing their specific target genes' expression. Compared to traditional biomarkers (e.g., mRNAs and proteins), miRNAs are more stable and can be readily screened and accurately quantitated and analyzed, making them ideal new-generation of biomarkers for early cancer detection and prognostic evaluation. Recent studies have shown that the changes of the expression levels of some serum miRNAs from ESCC patients significantly correlate with their diagnostic and prognostic outcome. In this review, we summarize the trend of the expression changes of miRNAs in ESCC patients' serum and discuss the possibility of detecting these miRNAs' expression changes as a novel method for ESCC early diagnosis and prognostic evaluation. Notably, the results of serum miRNAs from different detection methods are not completely consistent. Thus, we also discuss several possible reasons for such inconsistency.