Serum lincRNA-p21 as a potential biomarker of liver fibrosis in chronic hepatitis B patients

Serum long non-coding RNAs (lncRNAs) are emerging as promising biomarkers for various human diseases. The aim of this study was to investigate the feasibility of using serum long intergenic non-coding RNA-p21 (lincRNA-p21) as a biomarker for chronic hepatitis B patients. Serum lincRNA-p21 levels were quantified using real-time PCR in 417 CHB patients and 363 healthy controls. The promoter methylation level of lincRNA-p21 was detected using bisulphite-sequencing analysis in primary hepatic stellate cells (HSCs). Sera from hepatitis B-infected patients contained lower levels of lincRNA-p21 than sera from healthy controls. Serum lincRNA-p21 levels negatively correlated with stages of liver fibrosis in infected patients. Receiver operating characteristic (ROC) curve analyses suggested that serum lincRNA-p21 had a significant diagnostic value for liver fibrosis in these patients. It yielded an area under the curve of ROC of 0.854 with 100% sensitivity and 70% specificity in discriminating liver fibrosis from healthy controls. There was additionally a negative correlation between serum lincRNA-p21 level and the markers of liver fibrosis including -SMA and Col1A1. However, there was no correlation of serum lincRNA-p21 level with the markers of viral replication, liver inflammatory activity, and liver function. Notably, during primary HSCs culture, loss of lincRNA-p21 expression was associated with promoter methylation. Serum lincRNA-p21 could serve as a potential biomarker of liver fibrosis in CHB patients. Down-regulation of lincRNA-p21 in liver fibrosis may be associated with promoter methylation.