title: Expression of the PTEN tumor suppressor gene in malignant mammary gland tumors of dogs.
abstract: OBJECTIVE
  To determine whether changes in expression level of the phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) gene are associated with malignant transformation in mammary gland tumors in dogs.
  
  
  METHODS
  Specimens of 5 benign and 8 malignant mammary gland tumors and 2 unaffected mammary glands from dogs.
  
  
  METHODS
  The open reading frame (ORF) sequence of PTEN gene in each specimen was analyzed via a direct-sequencing method; expression levels of PTEN gene were quantified via a competitive reverse transcription (RT)-PCR method.
  
  
  RESULTS
  Compared with findings in clinically normal samples, amounts of PTEN mRNA were increased 2- to 4-fold in 4 of the 5 benign mammary gland tumor samples. In contrast, PTEN expression was remarkably low in 4 of the 8 malignant tumor samples (approx 12% to 37% of the level in unaffected mammary gland specimens). Gene amplification via the RT-PCR method with total RNA prepared from malignant tumor samples as a template yielded 3 bands that were smaller than the full-length ORF product of PTEN gene; in 2 of those 3 RT-PCR products, exons 6 and 7 or exons 3 to 8 were absent. No mutation was detected in the full-length ORF product of PTEN gene.
  
  
  CONCLUSIONS
  Results suggested that a decreased level of PTEN gene expression (compared with unaffected mammary gland tissue) is associated with malignancy in canine mammary tumors. Analysis of PTENgene expression level in dogs with mammary gland tumors may provide useful prognostic information.
authors.affiliation: Department of Veterinary Radiology, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyodai-Midorimachi, Ebetsu, Hokkaido 069-8501, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kanae
authors.forename: Daiji
authors.initials: D
authors.lastname: Endoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokota
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Taniyama
authors.forename: Masanobu
authors.initials: M
authors.lastname: Hayashi
mesh_terms: D000367:Age Factors; D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000662:veterinary*; D017931:DNA Primers; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D004587:Electrophoresis, Agar Gel / Q000662:veterinary; D005260:Female; D040461:Gene Components; D015972:Gene Expression Regulation, Neoplastic; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D051059:PTEN Phosphohydrolase