Gastroenterology

Gastroenterology

Volume 152, Issue 6, May 2017, Pages 1383-1394
Gastroenterology

Original Research
Full Report: Clinical—Liver
Genome-Wide Association Study Identifies TLL1 Variant Associated With Development of Hepatocellular Carcinoma After Eradication of Hepatitis C Virus Infection

https://doi.org/10.1053/j.gastro.2017.01.041Get rights and content
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Background & Aims

There is still a risk for hepatocellular carcinoma (HCC) development after eradication of hepatitis C virus (HCV) infection with antiviral agents. We investigated genetic factors associated with the development of HCC in patients with a sustained virologic response (SVR) to treatment for chronic HCV infection.

Methods

We obtained genomic DNA from 457 patients in Japan with a SVR to interferon-based treatment for chronic HCV infection from 2007 through 2015. We conducted a genome-wide association study (GWAS), followed by a replication analysis of 79 candidate single nucleotide polymorphisms (SNPs) in an independent set of 486 patients in Japan. The study end point was HCC diagnosis or confirmation of lack of HCC (at follow-up examinations until December 2014 in the GWAS cohort, and until January 2016 in the replication cohort). We collected clinical and laboratory data from all patients. We analyzed expression levels of candidate gene variants in human hepatic stellate cells, rats with steatohepatitis caused by a choline-deficient L-amino acid-defined diet, and a mouse model of liver injury caused by administration of carbon tetrachloride. We also analyzed expression levels in liver tissues of patients with chronic HCV infection with different stages of fibrosis or tumors vs patients without HCV infection (controls).

Results

We found a strong association between the SNP rs17047200, located within the intron of the tolloid like 1 gene (TLL1) on chromosome 4, and development of HCC; there was a genome-wide level of significance when the results of the GWAS and replication study were combined (odds ratio, 2.37; P = 2.66 × 10−8). Multivariate analysis showed rs17047200 AT/TT to be an independent risk factor for HCC (hazard ratio, 1.78; P = .008), along with male sex, older age, lower level of albumin, advanced stage of hepatic fibrosis, presence of diabetes, and higher post-treatment level of α-fetoprotein. Combining the rs17047200 genotype with other factors, we developed prediction models for HCC development in patients with mild or advanced hepatic fibrosis. Levels of TLL1 messenger RNA (mRNA) in human hepatic stellate cells increased with activation. Levels of Tll1 mRNA increased in liver tissues of rodents with hepatic fibrogenesis compared with controls. Levels of TLL1 mRNA increased in liver tissues of patients with progression of fibrosis. Gene expression levels of TLL1 short variants, including isoform 2, were higher in patients with rs17047200 AT/TT.

Conclusions

In a GWAS, we identified the association between the SNP rs17047200, within the intron of TLL1, and development of HCC in patients who achieved an SVR to treatment for chronic HCV infection. We found levels of Tll1/TLL1 mRNA to be increased in rodent models of liver injury and liver tissues of patients with fibrosis, compared with controls. We propose that this SNP might affect splicing of TLL1 mRNA, yielding short variants with high catalytic activity that accelerates hepatic fibrogenesis and carcinogenesis. Further studies are needed to determine how rs17047200 affects TLL1 mRNA levels, splicing, and translation, as well as the prevalence of this variant among other patients with HCC. Tests for the TLL1 SNP might be used to identify patients at risk for HCC after an SVR to treatment of HCV infection.

Keywords

Genetics
Liver Cancer
Mutation
Metalloprotease

Abbreviations used in this paper

AFP
α-fetoprotein
anti-HBc
antibody to hepatitis B core antigen
BMP1
bone morphogenetic protein 1
CCl4
carbon tetrachloride
CDAA
choline-deficient L-amino acid-defined
CHC
chronic hepatitis C
CI
confidence interval
CSAA
choline-sufficient L-amino acid-defined
EOT
end of treatment
GWAS
genome-wide association study
HBV
hepatitis B virus
HCC
hepatocellular carcinoma
HCV
hepatitis C virus
HR
hazard ratio
HSC
hepatic stellate cell
IFN
interferon
LC
liver cirrhosis
LD
linkage disequilibrium
mRNA
messenger RNA
NASH
non-alcoholic steatohepatitis
OR
odds ratio
RBV
ribavirin
SNP
single nucleotide polymorphism
SVR
sustained virologic response
TGF-β
transforming growth factor−β
TLD
tolloid
TLL
tolloid-like

Cited by (0)

Conflicts of interest These authors disclose the following: Yasuhito Tanaka is currently conducting research sponsored by Merck Sharp & Dohme, Corp, Chugai Pharmaceutical Co, Ltd, Bristol-Myers Squibb, and AbbVie Inc. Takashi Kumada received remuneration for lectures at meetings from Bristol-Myers Squibb. Yasuhiro Asahina belongs to a donation-funded Department funded by Toray Industries Inc., Chugai Pharmaceutical Co. Ltd, Merck Sharp & Dohme, Gilead Sciences Co. Ltd, and AbbVie GK. The remaining authors disclose no conflicts.

Funding This research was supported by the Research Program on Hepatitis from the Japan Agency for Medical Research and Development to Yasuhito Tanka and Katsushi Tokunaga, project code: 15fk0210018h0003 and 16fk0210101h0001.

Author names in bold designate shared co-first authorship.