Circulating Hypermethylated RASSF1A as a Molecular Biomarker for Diagnosis of Hepatocellular Carcinoma

BACKGROUND: Detection of circulating DNA can be applied for the diagnosis of many malignant neoplasms, including the hepatocellular carcinoma (HCC). The molecular pathogenesis of HCC is complex, involving different genetic and epigenetic alterations, chromosomal aberrations, gene mutations and altered molecular pathways. RASSF1A is a well-established tumor suppressor gene which suffers frequent inactivation due to promoter hypermethylation of CPG islands in multiple tumors including HCC, resulting in the reduction or loss of gene expression. OBJECTIVE: To examine the role of circulating RASSF1A as a non-invasive diagnostic marker for HCC. PARTICIPANT AND METHODS: A total of 45 HCC patients with a background of HCV infection, 40 cases of HCV infection without tumours and 40 apparently healthy controls were subjected to full history taking, clinical examination, routine laboratory investigations, assessment of serum AFP and detection of circulating hypermethylated RASSF1A gene by methylation-sensitive restriction enzyme digestion and real-time PCR. RESULTS: The level of hypermethylated RASSF1A was significantly elevated in the HCC group as compared to the HCV and control groups (p=0.001 for both). Copy number in serum was associated with increased tumor size (p value <0.001). On the other hand, no significant correlation was observed between RASSF1A and AFP (p=0.5). Using ROC curve analysis, the best cut-off for circulating serum RASSF1A to differentiate the HCC group was 8 copies/µl. CONCLUSION: The presence of hypermethylated RASSF1A in serum may be a useful and informative biomarker for HCC diagnosis and might be introduced as a screening method for populations at risk of HCC development.