Background: Somatic alterations on chromosome (Chr) 18q21-23, such as loss of heterozygosity (LOH), have been indicated as a critical step in bladder carcinogenesis. The aim of this study was to evaluate the prognostic role of LOH on Chr 18q21-23 in patients affected by low-grade, nonmuscle-invasive bladder cancer (NMIBC).
Materials and methods: A group of 108 consecutive subjects (65 affected by low-risk NMIBC and 43 controls) were selected for this prospective study. LOH on Chr 18 was assessed in the blood and urine samples. The primers used were D18S51, MBP LW, and MBP H. The data obtained were compared with follow-up information. Results were also analyzed by using artificial neural networks (ANN).
Results: Out of the 65 patients with NMIBC, 38 (58.4%) showed at least one alteration on Chr 18, while 27 (41.6%) showed no alteration. In the control group, only 2 out of 43 subjects showed LOH on Chr 18. At the end of follow-up, 29 patients were alive without recurrence, while 36 had at least one recurrence. A significant correlation between LOH on Chr 18 and status at follow-up was found (P = 0.022). Kaplan-Meier curves demonstrated a significant correlation between recurrence-free status and LOH on Chr 18 (P = 0.0003). At multivariate analysis, LOH on Chr 18 (P = 0.002) and the number of lesions (P = 0.03) were identified as independent predictors of recurrence-free probability. ANN analysis confirmed the results from multivariate analysis.
Conclusions: This study highlights the role of LOH analysis on Chr 18 in improving recurrence prediction in patients affected by low-grade NMIBC.
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