Abstract. The association between hepatocellular carcinoma (HCC) and the epidermal growth factor (EGF) 61A/G polymorphism has been analyzed in several studies, but results remain inconsistent. Therefore, the aim of the present study was to quantitatively summarize the association between the EGF 61A/G polymorphism and the risk of HCC. The PubMed and EMBASE databases were searched for studies published prior to May 1, 2014. The overall, subgroup and sensitivity analyses were conducted using Comprehensive Meta-Analysis software, version 2.2. In total, 12 published case-control studies, consisting of 2,095 patients with HCC and 3,766 control individuals, were included in the present study. Meta-analysis of the included studies revealed that EGF 61A/G polymorphism contributed to the risk of HCC under all four genetic models, consisting of the G vs. A (OR, 1.25; 95% CI, 1.11-1.40), GG vs. AA (OR, 1.53; 95% CI, 1.26-1.85), GG vs. AG + AA (OR, 1.34; 95% CI, 1.13-1.58) and GG + AG vs. AA (OR, 1.27; 95% CI, 1.08-1.49) comparisons. Subgroup analysis further suggested that EGF 61A/G polymorphism was associated with the risk of HCC in patients and control individuals with liver disease, based on ethnicity and source of control, respectively. No other significance in residual subgroup analysis was observed. The present meta-analysis suggests that the EGF 61A/G polymorphism is associated with an increased risk of HCC and may be a potential marker for liver disease, such as hepatitis B virus infection, hepatitis C virus infection and liver cirrhosis.
IntroductionHepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and develops predominately in individuals with liver cirrhosis (1). Cirrhosis is the strongest known risk factor for HCC, particularly cirrhosis resulting from infection with hepatitis C virus (HCV) or hepatitis B virus (HBV) (2,3). Additionally, heavy alcohol consumption, diabetes, obesity and tobacco use have been considered to contribute to the local burden of HCC (4,5). However, only a small number of people exposed to these risk factors develop HCC, suggesting that other environmental and genetic factors may play a role in HCC development. For this reason, the pathogenesis of HCC has not been fully elucidated.Additionally, numerous clinicians rely on serological α-fetoprotein testing and abdominal ultrasound imaging for HCC screening (6). However, these screening tools demonstrate low sensitivity and specificity (7-9) and the diagnoses of HCC are made late in the course of the disease. Therefore, early identification of molecular markers associated with an increased risk of HCC has been proposed as an alternative strategy for the diagnosis of HCC.Epidermal growth factor (EGF) was first isolated in 1962 (10) and plays a critical role in liver tissue regeneration (11). In previous years, numerous studies have revealed that the EGF signaling pathway with the EGF 61A/G polymorphism (rs4444903), a commonly functional single-nucleotide polymorphism (SNP) in the 5'-untranslated region of the EGF gen...