Person:

Lanuti, Michael

Context: Overexpression of epidermal growth factor (EGF) in the liver induces transformation to hepatocellular carcinoma in animal models. Polymorphisms in the EGF gene modulate EGF levels. Objective: To assess the relationship among human EGF gene single-nucleotide polymorphism, EGF expression, and risk of hepatocellular carcinoma. Design, Setting, and Participants: Molecular mechanisms linking the 61G allele polymorphism to EGF expression were examined in human hepatocellular carcinoma cell lines and human liver tissue. A case-control study involving 207 patients with cirrhosis was conducted at the Massachusetts General Hospital (1999-2006) and a validation case-control study involving 121 patients with cirrhosis was conducted at Hôpital Paul Brousse (1993-2006). Restriction fragment-length polymorphism was used to determine the EGF gene polymorphism genotype. Logistic regression analysis was used to assess the association between the EGF polymorphism and hepatocellular carcinoma risk. Main Outcome Measures: Mechanisms by which the EGF gene polymorphism modulates EGF levels and associations among EGF gene polymorphism, EGF levels, and hepatocellular carcinoma. Results: Transcripts from the EGF 61G allele exhibited more than a 2-fold longer half-life than those from the 61*A allele, and EGF secretion was 2.3-fold higher in G/G hepatocellular carcinoma cell lines than A/A cell lines. Serum EGF levels were 1.8-fold higher in G/G patients than A/A patients, and liver EGF levels were 2.4-fold higher in G/G patients than A/A patients. Among the 207 patients with cirrhosis in the Massachusetts study population, 59 also had hepatocellular carcinoma. Analysis of the distribution of allelic frequencies revealed that there was a 4-fold odds of hepatocellular carcinoma in G/G patients compared with A/A patients in the Massachusetts study population (odds ratio, 4.0; 95% confidence interval [CI], 1.6-9.6; P = .002). Logistic regression analysis demonstrated that the number of copies of G was significantly associated with hepatocellular carcinoma after adjusting for age, sex, race, etiology, and severity of cirrhosis (G/G or A/G vs A/A; hazard ratio, 3.49; 95% CI, 1.29-9.44; P = .01). The significant association was validated in the French patients with alcoholic cirrhosis and hepatocellular carcinoma. Conclusion: The EGF gene polymorphism genotype is associated with risk for development of hepatocellular carcinoma in liver cirrhosis through modulation of EGF levels.

Background: In the setting of chronic liver injury in humans, epidermal growth factor (EGF) and EGF receptor (EGFR) are up-regulated and have been proposed to have vital roles in both liver regeneration and development of hepatocellular carcinoma (HCC). Chronic liver injury also leads to hepatic stellate cell (HSC) differentiation and a novel subpopulation of HSCs which express CD133 and exhibit properties of progenitor cells has been described in rats. The carbon tetrachloride (CCl4)-induced mouse model has been historically relied upon to study liver injury and regeneration. We exposed mice to CCl4 to assess whether EGF and CD133+ HSCs are up-regulated in chronically injured liver. Methods: CCl4 in olive oil was administered to strain A/J mice three times per week by oral gavage. Results: Multiple well-differentiated HCCs were found in all livers after 15 weeks of CCl4 treatment. Notably, HCCs developed within the setting of fibrosis and not cirrhosis. CD133 was dramatically up-regulated after CCl4 treatment, and increased expression of desmin and glial fibrillary acidic protein, representative markers of HSCs, was also observed. EGF expression significantly decreased, contrary to observations in humans, whereas the expression of amphiregulin, another EGFR ligand, was significantly increased. Conclusions: Species-specific differences exist with respect to the histopathological and molecular pathogenesis of chronic liver disease. CCl4-induced chronic liver injury in A/J mice has important differences compared to human cirrhosis leading to HCC.