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Two molecular pathways to transitional cell carcinoma of the bladder
C H Spruck1, P F Ohneseit, M Gonzalez-Zulueta
1Kenneth Norris Jr. Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, University of Southern California, School of Medicine, Los Angeles 90033.
Cancer Research
|February 1, 1994
Summary
Bladder cancer progression differs based on tumor type. Papillary tumors often show chromosome 9 loss, while flat tumors (CIS) frequently acquire p53 mutations, leading to invasive disease.
Area of Science:
- Urology
- Oncology
- Genetics
Background:
- Noninvasive bladder transitional cell carcinomas exhibit distinct morphologies.
- Papillary tumors (T(a)) are multifocal and rarely progress.
- Flat tumors (carcinoma in situ, CIS) frequently progress to invasive disease.
Purpose of the Study:
- To investigate genetic alterations in bladder tumors with different morphologies.
- To determine the roles of chromosome 9 loss and p53 mutations in bladder carcinogenesis.
Main Methods:
- Analysis of 216 bladder tumors (various stages and histopathologies).
- Examination for loss of heterozygosity of chromosome 9.
- Detection of p53 gene mutations.
Main Results:
- Loss of chromosome 9 was more frequent in T(a) tumors (34%) than in CIS/dysplasia (12%).
- p53 mutations were significantly more common in CIS/dysplasia (65%) compared to T(a) tumors (3%).
- p53 mutation frequency in CIS/dysplasia was similar to muscle-invasive tumors (51%).
Conclusions:
- Two distinct genetic pathways may underlie bladder carcinogenesis, correlating with tumor morphology.
- p53 mutations in CIS/dysplasia likely contribute to genomic instability and disease progression.
- Chromosome 9 alterations may initiate T(a) tumors and contribute to CIS progression, with some cases showing divergent genetic pathways.