Analysis of DNA methylation in plasma for monitoring hepatocarcinogenesis.
OBJECTIVE
To explore whether the aberrant DNA methylation status in plasma could be used as a biomarker for hepatocellular carcinoma (HCC) screening among high-risk individuals.


METHODS
The promoter methylation status of ELF, RASSF1A, p16, and GSTP1 was investigated by methylation-specific polymerase chain reaction (PCR) in 34 paired HCC and nontumor liver tissue from HCC patients and 10 tissues from patients with liver cirrhosis (LC). Plasma samples from 31 HCC patients, 10 LC patients as well as 7 patients with benign hepatic conditions were also collected and characterized using the same method.


RESULTS
Among liver specimens, HCC tissues displayed a significantly higher methylation frequency of each gene compared with nontumor tissue (p<0.05). Moreover, the frequency was much higher in tumor tissues than in nontumor tissue, when the data from two or three genes were combined (p=0.001 and p<0.001, respectively). Among plasma samples, either the frequency of at least one methylated gene (p<0.001) or the average number of methylated genes (p<0.05) demonstrated a stepwise increase in patients with benign lesions, LC, and HCC. Furthermore, when positive results, that is, plasma methylation status of at least one gene were combined with the elevated AFP400 level (serum alpha-fetoprotein [AFP] level at a cutoff of 400 ng/mL), the diagnostic sensitivity of HCC could increase to 93.55%.


CONCLUSIONS
These results suggested that the methylation of tumor suppressor genes may participate in the development and progression of HCC. Additionally, it may be useful to combine the plasma DNA methylation status of a panel of gene markers and the serum AFP for HCC screening.
1 Department of Biochemistry and Molecular Biology, School of Preclinical and Forensic Medicine, West China Medical Center , Sichuan University, Chengdu, China .
Wenqing
W
Huang
2 Department of Dermatology, West China Hospital, Sichuan University , Chengdu, China .
Tong
T
Li
1 Department of Biochemistry and Molecular Biology, School of Preclinical and Forensic Medicine, West China Medical Center , Sichuan University, Chengdu, China .
Wenli
W
Yang
1 Department of Biochemistry and Molecular Biology, School of Preclinical and Forensic Medicine, West China Medical Center , Sichuan University, Chengdu, China .
Xinjuan
X
Chai
3 Division of Liver Transplantation, Department of Surgery, West China Hospital , Chengdu, China .
Kefei
K
Chen
1 Department of Biochemistry and Molecular Biology, School of Preclinical and Forensic Medicine, West China Medical Center , Sichuan University, Chengdu, China .
Ling
L
Wei
1 Department of Biochemistry and Molecular Biology, School of Preclinical and Forensic Medicine, West China Medical Center , Sichuan University, Chengdu, China .
Shuwang
S
Duan
3 Division of Liver Transplantation, Department of Surgery, West China Hospital , Chengdu, China .
Bo
B
Li
1 Department of Biochemistry and Molecular Biology, School of Preclinical and Forensic Medicine, West China Medical Center , Sichuan University, Chengdu, China .
Yang
Y
Qin
D000328:Adult; D063646:Carcinogenesis / Q000235:genetics*; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000097:blood*; D036383:Ephrin-A2 / Q000235:genetics; D005260:Female; D019942:Genes, p16; D051549:Glutathione S-Transferase pi / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood* / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D025521:Tumor Suppressor Proteins / Q000235:genetics
D004273:DNA, Neoplasm; D036383:Ephrin-A2; C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins; D051549:Glutathione S-Transferase pi