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Expression of the Bax inhibitor‐1 gene in pulmonary adenocarcinoma
Author(s) -
Tanaka Ryota,
Ishiyama Tadashi,
Uchihara Teruhito,
Inadome Yukinori,
Iijima Tatsuo,
Morishita Yukio,
Kano Junko,
Goya Tomoyuki,
Noguchi Masayuki
Publication year - 2005
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.21639
Subject(s) - adenocarcinoma , immunohistochemistry , cancer research , apoptosis , gene expression , in situ hybridization , gene , programmed cell death , biology , regulator , cancer , pathology , lung cancer , cell , medicine , genetics
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. Cancer 2006. © 2005 American Cancer Society.