Purpose: Amplification or gain of copy number of chromosome 20q13.2 has been implicated as a causal factor for chromosome instability. We investigated the impact of chromosomal instability and its causative molecular markers, 20q13.2 gain and centrosome amplification, on patient outcome in upper urinary tract transitional cell carcinoma (UUT-TCC).
Experimental design: The number of centrosomes was assessed by immunohistochemistry. Numerical aberrations of chromosomes 7, 9, and 17 that allowed the estimation of chromosomal instability and 20q13.2 gain were evaluated by fluorescence in situ hybridization in 96 frozen specimens from UUT-TCC and compared with clinicopathologic background and patient outcome.
Results: Chromosomal instability, 20q13.2 gain, and centrosome amplification were detected in 62 of 96 (64.6%), 61 of 96 (63.5%), and 45 of 90 (50.0%) tumors, respectively. 20q13.2 Gain was significantly associated with tumor stage (P = 0.042), chromosomal instability (P < 0.0001), and centrosome amplification (P < 0.0001). Kaplan-Meier analysis showed that 20q13.2 gain was strongly associated with intravesical recurrence-free survival in all patients (P = 0.0050), as well as in patients with grade 2 tumors (P = 0.0011, log-rank test). On multivariate analysis, 20q13.2 gain was found to be the sole independent prognostic factor predicting subsequent intravesical recurrence (hazard ratio, 1.65; 95% confidence interval, 1.03-2.90; P = 0.036).
Conclusions: 20q13.2 gain was strongly associated with a reduced time to intravesical recurrence in all patients. Our data suggest that 20q13.2 gain may be a predictive marker of intravesical recurrence in patients with UUT-TCC.