Long non-coding RNA UCA1 may be a novel diagnostic and predictive biomarker in plasma for early gastric cancer.

Gastric cancer (GC) is one of the most common malignancies and ranks the second leading cause of cancer death worldwide. The role of long non-coding RNAs (lncRNAs) in the gastric cancer pathogenesis is largely unknown. The present study is aimed to identify aberrantly expressed lncRNAs involved in the progression of GC. 33 lncRNAs showed significantly differential expression levels between gastric tumor samples and matched normal tissues from 5 pairs of samples using microarray assay. LncRNAs were classified into different subgroups. The expression levels of 4 lncRNAs: HIF1A-AS1, PVT1, CBR3-AS1 and UCA1 both in tumor and plasma were further confirmed in 20 gastric patients by real-time PCR assay. Then, the correlations between the tissue and plasma of these 4 lncRNA levels were assessed. Our data show that there was a significantly positive correlation of UCA1 expression levels between tumor tissues and plasma (r = 0.931). Furthermore, the specificity and sensitivity of PVT-1 and UCA1 were evaluated by receiver operating characteristic (ROC) curve. The results demonstrated that plasma UCA1 provided the higher diagnostic performance for detection of GC (AUC = 0.928; P < 0.001) than PVT-1 (AUC = 0.731; P < 0.01). Taken together, our study suggested that plasma UCA1 levels could be a promising candidate of noninvasive biomarker for GC early diagnosis.