Numerical aberrations of chromosome 9 in bladder cancer. A possible prognostic marker for early tumor recurrence

To investigate whether nonrandom aberrations of chromosomal numbers could predict tumor recurrence in patients with bladder cancer, archival urine cytology specimens (Giemsa-stained) from patients previously treated for transitional cell carcinoma of the urinary bladder were studied retrospectively by fluorescence in situ hybridization. A total of 48 patients (pTis, 6; pTa, 2: pT1, 32; and pT2-4, 8) were consecutively enrolled in this study, and numerical aberrations of chromosomes 9 and 17 were investigated. Cytology was diagnosed as negative for malignancy in 18 patients and positive in 30 patients. Twenty-seven of the 48 patients (56%) had one or more chromosomal aberrations. The frequency of numerical aberrations of chromosome 17 was correlated with increasing stage and grade, whereas loss of copies of chromosome 9 (monosomy) was frequently observed at a lower stage and grade. Chromosomal aberrations were detected in 9 (50%) of 18 patients with negative or equivocal cytology (class I, II, or III) by the Papanicolaou classification. Of eight patients with negative or equivocal cytology who developed tumor recurrence, four (50%) showed monosomy 9 and one (14%) showed a numerical aberration of chromosome 17. All six patients who showed monosomy of chromosome 9 developed tumor recurrence within 12 months, whereas four of the nine patients who did not show monosomy of this chromosome developed recurrence within 12 months (P<0.05, Fisher test). These results suggest that monosomy of chromosome 9 might be a prognostic marker for early tumor recurrence in patients with negative or equivocal cytology specimens.