Methylation of multiple genes in hepatitis C virus associated hepatocellular carcinoma

Abstract

We studied promoter methylation (PM) of 11 genes in Peripheral Blood Lymphocytes (PBLs) and tissues of hepatitis C virus (HCV) associated hepatocellular carcinoma (HCC) and chronic hepatitis (CH) Egyptian patients. The present study included 31 HCC with their ANT, 38 CH and 13 normal hepatic tissue (NHT) samples. In all groups, PM of APC, FHIT, p15, p73, p14, p16, DAPK1, CDH1, RARβ, RASSF1A, O6MGMT was assessed by methylation-specific PCR (MSP). APC and O6-MGMT protein expression was assessed by immunohistochemistry (IHC) in the studied HCC and CH (20 samples each) as well as in a different HCC and CH set for confirmation of MSP results. PM was associated with progression from CH to HCC. Most genes showed high methylation frequency (MF) and the methylation index (MI) increased with disease progression. MF of p14, p73, RASSF1A, CDH1 and O6MGMT was significantly higher in HCC and their ANT. MF of APC was higher in CH. We reported high concordance between MF in HCC and their ANT, MF in PBL and CH tissues as well as between PM and protein expression of APC and O6MGMT. A panel of 4 genes (APC, p73, p14, O6MGMT) classifies the cases independently into HCC and CH with high accuracy (89.9%), sensitivity (83.9%) and specificity (94.7%). HCV infection may contribute to hepatocarcinogenesis through enhancing PM of multiple genes. PM of APC occurs early in the cascade while PM of p14, p73, RASSF1A, RARB, CDH1 and O6MGMT are late changes. A panel of APC, p73, p14, O6-MGMT could be used in monitoring CH patients for early detection of HCC. Also, we found that, the methylation status is not significantly affected by whether the tissue was from the liver or PBL, indicating the possibility of use PBL as indicator to genetic profile instead of liver tissue regardless the stage of disease.

Hepatitis C: Host and Viral Factors Associated with Response to Therapy and Progression of Liver Fibrosis

“…It is believed that changes in DNA methylation patterns are early events in hepatocarcinogenesis and they can even occur at the early stages of HCV induced liver fibrosis [88]. This is supported by the results of the study conducted by Zekri et al, in which they demonstrated that methylation of certain host genes increase with liver disease progression, from fibrosis to HCC [89]. Moreover, the same group of authors has been shown that methylation of certain tumor suppressor genes affect the response to the antiviral therapy [90].…”

Association of FHIT expression and <em>FHIT</em> gene hypermethylation with liver cancer risk: a PRISMA-compliant meta-analysis

“…Several studies have reported that the low expression of FHIT and FHIT gene mutations were shown in the HCC cell lines and primary HCC tissues 33,36,37. Aberrant FHIT transcripts were found in 39%–70% of HCC patients 45.…”

“…These transcripts affected the normal expression and function of FHIT protein. From previous studies, these alternations were often identified in the exon 5 and 6, and single-point mutations were very rare 37,46,47. In addition, some studies were also conducted to explore the change of FHIT protein expression other than these structural variations of FHIT gene.…”

The Molecular Background Associated with the Progression of Hepatitis C to Hepatocellular Carcinoma

“…normal hepatic tissue (NHT); which represents the progression from NHT to HCC in the HCV genotype 4-infected persons [21]. Promotor methylation of these genes was assessed by methylation-specific PCR (MSP).…”

“…We assessed the protein expression of APC and O6MGMT in 20 NHT samples, 20 HCC and 20 CH tissues as well as in another group of samples including 40 NHT, 52 CH and 107 HCC tissue samples for confirmation of the methylation results [21]. In the original set, cytoplasmic immunostaining for the APC was detected in 11 cases of NHT (55%), with loss of staining in 10 CH cases (50%), and 15 cases of HCC group (75%).…”