Prognostic significance of insulin‐like growth factor (IGF) binding protein‐2 to IGF‐binding protein‐3 ratio in patients undergoing radical cystectomy for invasive transitional cell carcinoma of the bladder

Abstract

OBJECTIVES To analyse the prognostic significance of insulin‐like growth factor binding protein‐2 (IGFBP‐2) and IGFBP‐3 in patients having a radical cystectomy for invasive bladder cancer. PATIENTS AND METHODS Tissue samples of invasive bladder cancer were obtained from 97 patients who had radical cystectomy. The expression of IGFBP‐2 and IGFBP‐3 mRNAs in these samples was measured by real‐time reverse transcription‐polymerase chain reaction (RT‐PCR), and the findings analysed in relation to clinicopathological factors. RESULTS During the observation period, 31 patients (group A) developed disease recurrence, while the remaining 66 (group B) had no evidence of recurrence. The expression level of IGFBP‐2 mRNA was significantly higher in group A than in B, while IGFBP‐3 mRNA expression was significantly lower in group A than in B, and there was a significant difference in the relative expression ratio of IGFBP‐2 to IGFBP‐3 (BP‐2/BP‐3 ratio) between the groups. Recurrence‐free survival in patients with an elevated BP‐2/BP‐3 ratio was significantly lower than in those with a normal ratio. Multivariate analysis indicated that an elevated BP‐2/BP‐3 ratio, but not IGFBP‐2 and IGFBP‐3 mRNA levels, was an independent predictor of disease recurrence. CONCLUSIONS These findings suggest that the BP‐2/BP‐3 ratio measured by real‐time RT‐PCR could be useful for predicting disease recurrence in patients who have had a radical cystectomy for invasive bladder cancer.