Mutation analysis of the putative tumor suppressor gene PTEN/MMAC1 in hepatocellular carcinoma

Loss of heterozygosity of chromosome 10q has been reported in hepatoma. Are as,with a high rate of loss of genetic material could harbor putative turne r suppressor genes. PTEN/MMAC1, a candidate tumor suppressor gene located a t chromosome 10q23.3, has recently been identified and found to be homozygo usly deleted or mutated in several different types of human tumors. To dete rmine whether the PTEN/ MMAC1 gene is a target of 10q loss of heterozygosit y in hepatoma, we examined 42 primary hepatomas for mutations in PTEN/MMAC1 by using nested reverse transcriptase polymerase chain reaction (RT-PCR) o f the RNA and single-stranded conformation polymorphism (SSCP) analysis of all genomic exons. Although 2 of 42 hepatoma tissues had aberrant transcrip ts, 5 matched noncancerous liver tissues also had aberrant transcripts. Sou thern blot analysis of the entire genomic DNA revealed no genomic change. T herefore, like the TSG101 or FHIT gene, aberrant transcripts of PTEN/MMAC1 using the nested RT-PCR method were a common phenomenon for both cancerous and noncancerous liver tissues, which may nor be related to oncogenesis. No ne of the 42 cases had small deletions, point mutations, or insertions. Our results suggest that the PTEN/MMAC1 gene may not play a role in the pathog enesis of hepatoma.