Tobacco smoke, recurrences, and p53/bcl-2 expression in bladder cancer.
Overexpression of p53 is considered to be predictive of mutations of the p53 gene. Exposure-specific mutations of the p53 gene have been described for cancers at different sites. An association between p53 mutation/overexpression and smoking has been described in early stage bladder cancer, but results were conflicting. We have conducted a study on 131 bladder cancer cases, considering p53 expression and smoking habits in an area where the use of air-cured tobacco, rich in carcinogenic arylamines, is common. The study suggests that the use of air-cured tobacco induces p53 overexpression (possibly via mutation) in early stage-low grade bladder cancer, more frequently than flue-cured tobacco (odds ratios = 3.4, 95% confidence intervals 0.9-13 in stage 1; odds ratios = 24, 95% confidence intervals 1.1-519 in stage 1, grade 1). However, all the excess associated with air-cured tobacco was concentrated in recurrences. When available, the biopsies of recurrent cases with early-stage disease were re-examined and all showed p53 expression at first diagnosis (with 10-50% of cells positive) (n = 5). It is hypothesized that exposure to tobacco-related chemicals increases the risk of recurrences via p53 overexpression/mutation. Expression of the bcl-2 gene was detected in only 2 out of 13 p53-positive smokers.
Pacchioni
D
D
Dipartimento di Scienze Biomediche e Oncologia Umana, University of Torino, Italy.
Martone
T
T
Ghisolfi
G
G
Bussolati
G
G
Tizzani
A
A
Casetta
G
G
Vineis
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012907:Smoking / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D001749:Urinary Bladder Neoplasms / Q000378:metabolism*
D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53