Liver tissues and corresponding blood samples were previously collected from 150 patients of Caucasian ethnicity (71 males and 79 females) undergoing liver surgery at the Campus Virchow (University Medical Center Charité, Humboldt University, Berlin, Germany). The average age of the subjects was 58±14 years. This study was approved by the ethics committees of the medical faculties of the Charité, Humboldt University, and of the University of Tuebingen and conducted in accordance with the Declaration of Helsinki. All tissue samples were examined by a pathologist and only histologically non-tumorous tissues were used. Clinical patient documentation available for all samples and shown to have significant influence on the analysis included age, sex, medical diagnosis (primary or secondary liver tumor, other diagnosis), presurgical medication (regular drug treatment before surgery vs no drugs), cholestatic liver injury (based on liver function tests22) and alcohol drinking and smoking habits. Patients with hepatitis, cirrhosis or chronic alcohol use were excluded. Detailed information on sample metadata is given in Supplementary Table S1.
