Identification of four serum microRNAs from a genome-wide serum microRNA expression profile as potential non-invasive biomarkers for endometrioid endometrial cancer

Serum microRNAs (miRNAs), with their remarkable stability and unique concentration profiles in patients with various diseases, are promising non-invasive biomarkers for tumor detection. The present study investigated the altered profiles of serum microRNAs in patients with endometrioid endometrial cancer (EEC) in order to predict the malignancy of the disease at a relatively early stage. TaqMan(®) low-density arrays (TDLAs) were used to perform an analysis in the initial screening phase using serum samples pooled from seven EEC patients and 20 controls. The differential expression was validated using a hydrolysis probe-based stem-loop quantitative reverse transcription polymerase chain reaction (qRT-PCR) in samples taken from 26 EEC patients and 22 age- and gender-matched healthy controls. The data obtained from the TLDAs demonstrated that 22 serum miRNAs were markedly upregulated in the EEC patients compared with the controls. The qRT-PCR analysis further identified a profile of four serum miRNAs (miR-222, miR-223, miR-186 and miR-204) as a fingerprint for EEC detection. The area under the receiver operating characteristic (ROC) curve of this four-serum miRNA signature was 0.927, which was markedly higher than that of carbohydrate antigen 125 (CA-125; 0.673). The four-miRNA signature identified by genome-wide serum miRNA expression profiling analysis provides a novel, non-invasive approach for EEC diagnosis.