In situ detection of global DNA hypomethylation in exfoliative urine cytology of patients with suspected bladder cancer.
Global DNA hypomethylation is a common phenomenon in bladder cancer. Therefore we investigated whether it is possible to detect and assess global DNA hypomethylation in bladder cancer using a specific monoclonal antibody for 5-methyl-cytosine. Cytospins from exfoliative urine cytology specimens of patients with bladder cancer or a history of bladder cancer, control patients with benign urological diseases and of young healthy volunteers were analyzed. Urothelial carcinoma (UC) cells showed various degrees of nuclear destaining indicating global DNA hypomethylation whereas all specimens from healthy volunteers showed granular nuclear staining indicating regular methylation of repeated DNA sequences. Lowest 5-methylcytosine immunostaining scores were observed in carcinoma cells and a statistically significant difference was observed between urothelial cells of healthy controls or patients with benign disease compared to bladder cancer patients (p<0.01, p<0.05, respectively). In UC cases even morphologically normal urothelial cells often displayed evident hypomethylation. Likewise, in patients with a history of UC, but no cystoscopic evidence of recurrence, morphologically non-malignant urothelial cells presented with some degree of demethylation. Our results strongly support the hypothesis of early global demethylation in bladder cancer. Immunocytochemical staining with the 5-methylcytosine antibody allows simultaneous individual assessment of nuclear morphology and methylation status of a given sample.
Seifert
Hans-Helge
HH
Department of Urology, University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany. seiferth@uni-duesseldorf.de
Schmiemann
Viola
V
Mueller
Mirko
M
Kazimirek
Marietta
M
Onofre
Fabiana
F
Neuhausen
Anne
A
Florl
Andrea R
AR
Ackermann
Rolf
R
Boecking
Alfred
A
Schulz
Wolfgang A
WA
Grote
Hans Juergen
HJ
D044503:5-Methylcytosine / Q000378:metabolism*; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D015139:Blotting, Southern; D003581:Cytodiagnosis / Q000379:methods; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000652:urine*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D001749:Urinary Bladder Neoplasms / Q000652:urine*
D000911:Antibodies, Monoclonal; D004273:DNA, Neoplasm; D044503:5-Methylcytosine