DNA cytometry and chromosome 9 aberrations by fluorescence in situ hybridization of irrigation specimens from bladder cancer patients.

OBJECTIVES: To determine the sensitivity and specificity of combining fluorescence in situ hybridization (FISH) measurement of chromosome 9 and DNA cytometry of bladder irrigation specimens in the detection of bladder cancer. METHODS: Bladder irrigation specimens were obtained from 37 normal control patients and 317 bladder cancer patients during cystoscopic examinations. Bladder cancer patients were sampled in the absence of observable tumor (256 specimens) and concurrently with tumor (204 specimens). Chromosome 9 copy number was determined on a cellular basis by FISH, and cellular DNA content was determined by Feulgen DNA staining and image cytometry. RESULTS: Sensitivity of chromosome 9 FISH was 42% for all tumors and was not correlated to transitional cell carcinoma tumor grade, while the sensitivity of DNA cytometry was 55% and improved with increasing grade from 38% for grade 1 to 90% for grade 3 tumors. The results of FISH and DNA cytometry were combined, resulting in specificity of 92% and sensitivity of 69% for grade 1, 76% for grade 2, and 97% for grade 3 tumors. CONCLUSIONS: The lack of increase with grade in the percentage of positive specimens by FISH supports the hypothesis that chromosome 9 aberrations are critical events in bladder tumorigenesis for many patients. These data demonstrate the presence of cells in irrigation specimens with specific genomic lesions of chromosome 9 and DNA content. Combining FISH on chromosome 9 and DNA cytometry provides an increase in sensitivity to transitional cell carcinoma over either test alone.

Loss of the CDKN2A/p16 locus detected in bladder irrigation specimens by fluorescence in situ hybridization.

PURPOSE: We measured the CDKN2A/p16 tumor suppressor gene locus in bladder irrigation specimens and correlated the measurement with the clinical status of patients with bladder cancer. MATERIALS AND METHODS: Irrigation specimens were obtained at cystoscopy from 10 normal controls, 21 patients with bladder cancer in whom no concurrent bladder tumor was seen and 23 patients with bladder tumors. Deoxyribonucleic cytometry and fluorescence in situ hybridization measurements were made. One fluorescence in situ hybridization probe was specific to the chromosome 9 centromere and the other, COSp16, targeted the CDKN2A/p16 region on chromosome 9p21. Three rates were calculated, including the hyperdiploid fraction from deoxyribonucleic acid cytometry, disomic fraction from the 9 centromere count and COSp16F, the frequency of COSp16 in association with 9 centromere. Specimens were classified as positive or negative for each of these rates using cutoff points based on previous studies and the distribution of values obtained for the normal control specimens. RESULTS: Hyperdiploid fraction values were positive (greater than 8%) in 1 normal and 1 nontumor specimen. Ten specimens from patients with tumor showed elevated hyperdiploid fraction values. In 4 nontumor and 13 tumor irrigation specimens the chromosome 9 disomic fraction values were positive (less than 80%). COSp16F was positive (less than 83%) for 18 nontumor irrigation specimens and 18 tumor irrigation specimens. One normal, and 39 of 44 nontumor and tumor irrigation specimens were positive by at least 1 test. CONCLUSIONS: COSp16 loss is measurable in irrigation specimens and it correlates with clinical status. This assay may prove useful in screening for and managing bladder cancer.