To investigate gene-environment interactions based on large samples,24

this study consisted of 1156 HCC cases (including 635 previously studied subjects7, 25) and 1402 control individuals (including 712 previously studied subjects7, 25). All cases and controls were recruited from affiliated hospitals of the two main medical colleges in southwestern Guangxi (Guangxi Medical University and Youjiang Medical College for Nationalities) from January 2005 to November 2009. All cases and controls were residents of the Guangxi Zhuang Autonomous Region from AFB1 exposure areas and accepted enrollment in this study. The cases included in this study, representing a significant proportion (>90%) X-396 ic50 of HCC patients in the Guangxi population, were identified by histopathological diagnosis

in 100% of the HCC cases. During the same period, controls without any evidence of liver disease were randomly selected from a pool of healthy volunteers who visited the general health check-up centers of the same hospitals for their routinely scheduled physical examinations supported by local governments. To control the effects of confounders that were likely risk factors for Guangxi HCC patients, cases were individually matched (1:1 or 1:2) to controls with respect to age (±5 years), ethnicity (Han or minority), hepatitis B virus (HBV) infection status, and hepatitis C virus (HCV) infection status. Every potential control was first surveyed with a short questionnaire to elicit willingness to participate in the study and Selleck LY2606368 to provide preliminary demographic data for matching. With written, informed consent, the characteristic information for each subject, including age, gender, ethnicity, HBV infection status, and HCV L-NAME HCl infection status, was gathered with a standard interviewer-administered questionnaire and/or from medical records by a Youjiang Cancer Institution staff member; at the same time, 4 mL of

peripheral blood was obtained for the extraction of genomic DNA. Additionally, we collected clinical pathological data (including the cirrhosis status, tumor size, and tumor stage) from case medical records for 834 HCC patients receiving the same surgical resection treatment for the evaluation of the severity of liver disease and surgically removed samples for the analysis of XPC expression levels. Liver cirrhosis was diagnosed by pathological examination, and the tumor stages were confirmed according to the TNM system. Those who were hepatitis B surface antigen (HBsAg)–positive and anti-HCV–positive in their peripheral serum were defined as HBV-infected and HCV-infected. One hundred percent of those asked to take part in this study who did enroll agreed to participate in the investigative study.