Bax and Bcl-2 protein expression in gastric precancerous lesions: immunohistochemical study.
OBJECTIVE
Bcl-2 protein prolongs cell survival in the face of classical apoptotic stimuli, and is considered to be a suppressor of apoptosis. Bax plays a key role in apoptosis by accelerating cell death after an apoptotic stimulus. The aim of our study was to determine the roles of the Bax proapoptotic gene and the Bcl-2 antiapoptotic gene in the carcinogenesis of gastric cancer.


METHODS
One hundred and forty-five gastric biopsy specimens of chronic gastritis, atrophic gastritis, intestinal metaplasia and gastric dysplasia were studied. Using immunohistochemical methods, Bax and Bcl-2 protein expression was observed.


RESULTS
Bax was expressed in epithelial cells in all cases of chronic gastritis. Bax was not detected in 26% of specimens of atrophic gastritis. As intestinal metaplasia develops, Bax is further suppressed. In biopsy samples with dysplasia, Bax expression was demonstrated only in 12% of biopsy samples. Although Bcl-2 protein was not detected in chronic gastritis, aberrant expression was found in gastric epithelial intestinal metaplasia and dysplasia.


CONCLUSIONS
The suppression of Bax and overexpression of Bcl-2 protein is an early event in gastric tumorigenesis, before gastric dysplastic changes occur.
Anagnostopoulos
George K
GK
Gastroenterology Clinic, 251 Hellenic Air Force and Veterans General Hospital, Athens, Greece. gkanagnostopoulos@yahoo.gr
Stefanou
Dimitrios
D
Arkoumani
Evdokia
E
Sakorafas
George
G
Pavlakis
George
G
Arvanitidis
Dimitrios
D
Tsianos
Epameinondas
E
Agnantis
Niki J
NJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D005260:Female; D005756:Gastritis / Q000378:metabolism; D005757:Gastritis, Atrophic / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000473:pathology; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D011230:Precancerous Conditions / Q000378:metabolism* / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein