An assessment of chromosomal alterations detected by FISH in urothelial carcinoma and its correlation to liquid-based urine cytology and histopathology.

BACKGROUND

The present study aimed to evaluate the diagnostic usefulness, sensitivity, and specificity of urinary liquid-based cytology (LBC) versus multitarget, multicolor UroVysion fluorescence in situ hybridization (uFISH) assay for the diagnosis of urinary bladder cancer in light of the histological diagnosis.

METHODS

Fifty patients and negative controls each were selected for the study. A 10 ml voided urine specimen was processed for urine cytology to prepare LBC smears. For urinary FISH analysis, 50 ml of voided urine was processed using multi-target FISH-containing probes for the centromeres of chromosomes 3, 7, and 17 and the 9p21 locus. Histopathological examination of transurethral resection of bladder tumor (TURBT) chips was performed on diseased cases only.

RESULTS

All 50 diseased cases exhibited 62%, 80%, 76%, and 68% of uFISH sensitivity, uFISH specificity, positive predictive value (PPV) and negative predictive value (NPV) respectively. Among negative controls, results of 40%, 84%, 71%, and 58% for LBC sensitivity, LBC specificity, PPV, and NPV were found, respectively. Among the diseased cases uFISH positivity of 20%, 45%, 83.3%, 82.4% and 100% for Ta, T1, T2a, T2b and T3 respectively. Among the diseased cases LBC positivity was 0%, 20%, 33.3%, 70% and 100% for Ta, T1, T2a, T2b and T3 respectively.

CONCLUSION

Increased sensitivity and specificity of uFISH than LBC urine to detect urothelial carcinoma (UC) reflect the better potentiality of the former to detect UCs. The limitations of uFISH analysis include sophisticated equipment, higher cost, and experienced cytopathologists/technicians. It is proposed to conduct more such prospective trials with recent biomarkers so as to reduce the frequency of cystoscopy in such patients.