Laser capture microdissection analysis reveals frequent allelic losses in papillary urothelial neoplasm of low malignant potential of the urinary bladder.
BACKGROUND
In the 1999 World Health Organization classification system, papillary tumors of the urinary bladder were classified as papilloma, papillary urothelial neoplasm of low malignant potential (PUNLMP), and as Grade 1, Grade 2, and Grade 3 urothelial carcinoma. The biologic potential of PUNLMP of the urinary bladder is controversial. To the authors' knowledge, information regarding the genetic changes of PUNLMP tumors of the bladder is limited.


METHODS
The authors examined loss of heterogygosity (LOH) at 5 polymorphic microsatellite markers on chromosome 9q32-33 (D9S177), 9p22 (IFNA), 17p13.1 (TP53), 12q14-24 (D12S1051), and 3p25-26 (D3S3050) from 26 patients who were diagnosed with PUNLMP tumors of the urinary bladder. Tumors were microdissected from sections prepared from formalin-fixed, paraffin-processed tissue specimens using laser capture microdissection.


RESULTS
LOH was found in 21 of 26 (81%) patients with PUNLMP. The rate of LOH was 41% with D9S177, 32% with IFNA, 29% with TP53, 26% with D12S1051, and 44% with D3S3050. Allelic loss of multiple chromosome loci was often present in patients with PUNLMP tumors.


CONCLUSIONS
Genetic changes that commonly occur in advanced bladder carcinoma (> or = pT2) are frequently found in PUNLMP of the urinary bladder.
Cheng
Liang
L
Department of Pathology and Laboratory Medicine, School of Medicine, Indiana University Medical Center, University Hospital 3465, 550 North University Boulevard, Indianapolis, IN 46202, USA. lcheng@iupui.edu
MacLennan
Gregory T
GT
Zhang
Shaobo
S
Wang
Mingsheng
M
Pan
Chong-Xian
CX
Koch
Michael O
MO
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002295:Carcinoma, Transitional Cell / Q000235:genetics* / Q000473:pathology; D005260:Female; D006801:Humans; D007834:Lasers; D019656:Loss of Heterozygosity; D008297:Male; D042282:Microdissection; D018895:Microsatellite Repeats; D008875:Middle Aged; D010212:Papilloma / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D001749:Urinary Bladder Neoplasms / Q000235:genetics* / Q000473:pathology; D019459:Urothelium / Q000473:pathology*