High-throughput tissue microarray analysis of erbB-2 gene amplification in urinary bladder cancer. A study of Bulgarian patients.
BACKGROUND
Overexpression of the receptor Her-2 leads to increased proliferative response to epidermal growth factors which plays a key role in tumor development and growth. Increased oncoprotein level, in the majority of cases, is caused by erbB-2 gene amplification. To define the frequency of amplifications of erbB-2 in bladder cancer, and to determine their association with the tumor phenotype we utilized tissue microarray (TMA) approach.


METHODS
We analyzed a TMA consisting of 159 transitional cell bladder carcinomas for erbB-2 gene amplification by dual-color FISH.


RESULTS
The frequency of erbB-2 amplification was 5.3% of all successfully analyzed samples (4 of 75). It increased from minimally invasive (pT1) to muscle-invasive (pT2-4) tumors, as well as with advanced tumor grade (G1 to G2 to G3). All amplifications were cluster amplifications confirming the fact that erbB-2 amplification occurs intrachromosomally in bladder cancer.


CONCLUSIONS
We concluded that despite its low incidence, erbB-2 amplification is of importance for the bladder tumor invasion and progression.
Toncheva
Draga I
DI
Department of Medical Genetics, Medical University of Sofia, Sofia, Bulgaria. draga@spnet.net
Zaharieva
Boriana M
BM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002031:Bulgaria; D005260:Female; D018734:Genes, erbB-2 / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D001749:Urinary Bladder Neoplasms / Q000235:genetics*