Methylated cyclin D2 gene circulating in the blood as a prognosis predictor of hepatocellular carcinoma

BackgroundPrognosis of hepatocellular carcinoma (HCC) remains poor because of high recurrence rate. We examined preoperatively the methylated CCND2 gene levels present in the serum following release from HCC cells as a prognosis predictor in patients undergoing curative hepatectomy.MethodsQuantitative real-time RT-PCR and quantitative methylation-specific PCR were used to measure methylated CCND2 gene and its mRNA levels.ResultsThe CCND2 mRNA levels were down-regulated in HCC with early intrahepatic recurrence (IHR) within 1 year of curative hepatectomy. We also identified that this down-regulation was due to promoter hypermethylation. In 70 HCC patients who underwent curative hepatectomy, 39 patients sero-positive for the methylated CCND2 gene (> 70 pg/ml serum) exhibited a significantly shorter disease-free survival (DFS) period (P = 0.02) than the 31 patients who were sero-negative for the methylated CCND2 gene. None of the sero-negative patients demonstrated early IHR, and this method of serum testing did not produce any false-negative predictions for early IHR. Multivariate analysis showed that the serum level of methylated CCND2 was an independent risk factor for DFS (hazard ratio of 1.866, 95% CI: 1.106–3.149).ConclusionMethylated CCND2 gene in the serum serves as a prognosis predictor of HCC after curative hepatectomy.