title: Expression of the Bax inhibitor-1 gene in pulmonary adenocarcinoma.
abstract: BACKGROUND
  The regulation of programmed cell death, or apoptosis, is crucial for normal development and for the maintenance of homeostasis. It has been shown that the novel antiapoptotic protein Bax inhibitor-1 (BI-1) represents a new type of regulator of cell death pathways controlled by Bcl-2 and Bax.
  
  
  METHODS
  Surgically resected lung specimens were obtained from 32 patients with peripheral adenocarcinomas, and BI-1 gene expression was examined and compared with expression of the p53, bcl-2 and Bax genes.
  
  
  RESULTS
  Fourteen of 32 tumors (43.8%) were positive for BI-1 gene expression by in situ hybridization. BI-1 gene expression in tumor specimens was significantly higher in adenocarcinomas with bronchioloalveolar carcinoma (BAC) and in adenocarcinomas of mixed subtypes with bronchioloalveolar spreading (14 of 17 tumors; 82.4%) than in carcinomas without it spreading. Patients who had BI-1-positive adenocarcinoma showed a relatively favorable prognosis compared with patients who had BI-1-negative adenocarcinoma. Eleven of 32 tumors (34.4%) were positive for the p53 protein, only 1 of 32 tumors (3.1%) was positive for the Bcl-2 protein, and 26 of 32 tumors (81.3%) were positive for the Bax protein. Protein expressions of p53, Bcl-2, and Bax, as detected by immunohistochemistry, were not associated with BI-1 gene expression.
  
  
  CONCLUSIONS
  BI-1 gene expression was restricted to tumor cells with lepidic growth and was a prognostic factor for peripheral-type adenocarcinoma. It is believed that BI-1 gene expression is conserved evolutionarily and may act as a key regulator of the apoptotic pathway in BAC.
authors.affiliation: Department of Thoracic Surgery, Gunma Prefectural Cancer Center, Gunma, and Department of Pathology, Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Tanaka
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishiyama
authors.forename: Teruhito
authors.initials: T
authors.lastname: Uchihara
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Inadome
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Iijima
authors.forename: Yukio
authors.initials: Y
authors.lastname: Morishita
authors.forename: Junko
authors.initials: J
authors.lastname: Kano
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Goya
authors.forename: Masayuki
authors.initials: M
authors.lastname: Noguchi
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D000368:Aged; D017209:Apoptosis / Q000235:genetics*; D051017:Apoptosis Regulatory Proteins; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D011379:Prognosis; D011506:Proteins / Q000032:analysis* / Q000235:genetics
chemical_list: D051017:Apoptosis Regulatory Proteins; D008565:Membrane Proteins; D011506:Proteins; C484209:TMBIM6 protein, human