Lnc-PCDH9-13:1 Is a Hypersensitive and Specific Biomarker for Early Hepatocellular Carcinoma

BACKGROUND: Long non-coding RNAs (lncRNAs) show great potential as diagnostic tools in many diseases. We aimed to develop sensitive and noninvasive biomarkers in saliva for detecting early hepatocellular carcinoma (HCC). METHODS: Candidate lncRNA biomarkers identified by Agilent microarray were subjected to validation using qPCR for the quantification of their expression levels in independent tissue, plasma and saliva sample sets, including healthy controls, HBsAg carriers, patients with chronic Hepatitis B, liver cirrhosis, early HCC, and advanced HCC. Levels of candidate biomarkers were also measured in totally 108 saliva samples from patients with any one of other nine leading causes of cancer death in men and women. FINDINGS: Lnc-PCDH9-13:1 was significantly elevated in HCC tissues, plasma and saliva of HCC patients compared with healthy controls and groups of several benign liver diseases and other leading cancers. Its level was significantly reduced after curative hepatectomy but significantly elevated again if HCC recurrence occurred. Salivary lnc-PCDH9-13:1 showed reasonable specificities and sensitivities for detecting HCC compared with several control groups. Furthermore, the overexpression of lnc-PCDH9-13:1 promotes cell proliferation and migration in vitro. INTERPRETATION: Salivary lnc-PCDH9-13:1 is a desirable biomarker for early HCC. It may help warrant prospective validation with larger sample sizes in multi-centers.