Using a polymerase chain reaction (PCR) method, we tested for the hepatic mitochondrial DNA (mtDNA) deletion in 40 hepatic tumors (28 hepatocellular carcinomas [HCCs], 9 other malignant tumors, and 3 benign tumors) and in the livers of 71 patients, including 16 pediatric patients with end-stage liver disease who underwent living related donor liver transplantation and 16 liver donors. A 4977 base pair (bp) deletion of mtDNA was detected in 36 of 55 specimens of non-tumor portions of adult liver (65.5%). However, none of the specimens obtained from cirrhotic livers of the 16 pediatric patients younger than 13 years of age had the 4977 bp deletion. The frequency of mtDNA deletion was significantly decreased compared with normal liver in HCCs (7 of 28) and other malignant liver tumors (2 of 9). The frequency of this deletion was unrelated to the presence of liver cirrhosis, patient's gender, hepatitis B virus surface antigen status, and hepatitis C virus antibody status. (HEP-ATOLOGY 1995; 2 1: 1547-155 1 .)
Human mitochondria contain their own DNA, which codes for 13 peptides that comprise portions of multisubunit enzymes in the inner mitochondrial membrane, and also codes for 2 ribosomal RNAs and 22 transfer RNAs.' Specific deletions of mitochondrial DNA (mtDNA) have been detected by Southern blot analysis in skeletal muscle and other tissues of patients with the rare neuromuscular diseases, Kearns-Sayre syndrome, and progressive external ophthal-m~plegia.'-~ Recently, more than 10 different types of deletions have been identified in the mtDNA of various tissues of healthy individuals using polymerase chain reaction (PCR) r n e t h ~d s . ~ Among these, the 4977 base pair (bp) deletion is the most prevalent one found in the Abbreviations: mtDNA, mitochondrial DNA; PCR, polymerase chain reaction; bp, base pair; RTI, redox tolerance index; HCC, hepatocellular carcinoma; KBR, ketone body ratio.