Quantitative promoter methylation analysis of hepatocellular carcinoma, cirrhotic and normal liver

Abstract

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Little is known about its molecular pathogenesis and the relevance of DNA methylation for disease initiation and progression. Nevertheless, promoter methylation of some genes has been implicated as potential marker for HCC. Thirty-four HCC, 34 matching non-malignant, cirrhotic livers and 16 normal livers were analyzed for the methylation status of the genes p16 INK4a , GSTP1, MGMT, DAP-K and APC by quantitative methylation-specific PCR. DNA promoter methylation frequencies in HCC and matching non-malignant cirrhotic liver, respectively, were as follows: p16 INK4a (76% vs. 24%), GSTP1 (53% vs. 32%), MGMT (6 vs. 12%), DAP-K (68 vs. 100%) and APC (100 vs. 100%). GSTP1 and/or p16 INK4a promoter methylation was observed in 88% of the HCC samples. In normal liver tissue, the p16 INK4a , GSTP1 and MGMT promoter were not methylated. DAP-K was methylated in 31% and APC even in 100% of normal liver samples. Quantitative levels of methylated promoter DNA of all genes were significantly different in the various tissue types except for MGMT. Our results suggest that promoter methylation of tumor-associated genes is a common event in hepatocarcinogenesis. Significantly, higher levels and frequencies of promoter methylation in HCC were found for p16 INK4a and GSTP1 compared to non-malignant cirrhotic liver. This indicates that these epigenetic events may serve as a good marker for HCC. These data also demonstrate the importance of the quantification of methylated promoter DNA within a given sample and the use of normal tissue as controls. Quantitative analyses of methylated GSTP1 and p16 INK4a promoter may serve as a powerful molecular marker in detecting HCC in biopsies.

Methylation of multiple genes as molecular markers for diagnosis of a small, well‐differentiated hepatocellular carcinoma

“…15,[29][30][31][32] However, our results showed that CDKN2A remained unmethylated in 2 independent groups of HCC samples, the filtering and validation groups (data not shown), indicating poor performance in the detection of early HCC. These differences in methylation status may be due to differences in the location of CpG islands analyzed in both the present and previous studies.…”

Epigenetic Modifications in Hepatic Stellate Cells Contribute to Liver Fibrosis

“…For example, in a qualitative investigation using methylation-specific PCR (MSP) to detect various gene methylation status, the hypermethylation rate of promoter was found to be 15% in liver cirrhosis tissue and 0% in normal liver tissue (Zhang et al 2008). Furthermore, a direct quantitative investigation showed the methylation rate of several hepatopathy related genes are distinct between HC patients and normal controls: p16INK4a (24% and 0%), GSTP1 (32% and 0%), MGMT (12% and 0%) and DAP-K (100% and 31%) (Harder et al 2008). All these unintentionally discovered results have revealed it is still under doubt whether or not abnormal methylation on fibrosis-related genes is related to liver fibrosis.…”

Chromosome 8p as a potential hub for developmental neuropsychiatric disorders: implications for schizophrenia, autism and cancer

“…392 Nevertheless, other studies failed in finding this association. 393,394 Defects in tumor-suppressor APC gene, which is associated with colon and other cancers, 395,396 are also associated with susceptibility to schizophrenia; furthermore, APC is upregulated in patients with schizophrenia. 372 APC is a key component of the Wnt/ Winless signaling transduction pathway, which plays important roles in a number of developmental processes and in tumorigenesis.…”