Ask the Doctor

Summer 2007

Many thanks to Dr. Cheryl Lee, Assistant Professor of Urology, University of Michigan, and Chair of BCAN’s Scientific Advisory Board, for responding to our questions below.

Q. How often does an individual with recurrent low-grade papillary tumors develop more aggressive high grade tumors?

A. Low grade papillary tumors are commonly seen in bladder cancer patients. These tumors, also termed Ta tumors (Stage 0a), arise on the surface of the bladder mucosa (superficial bladder lining). These tumors can become more “aggressive” if they begin to penetrate the bladder wall (stage progression) or if the appearance of their cells change into a “high” grade (grade progression). Although low grade tumors recur in 50- 70% of cases, they rarely progress in stage. In a Swedish study reported in 1999, 255 patients presenting with low grade Ta bladder tumors were followed over time. Only 2.4% of patients progressed to a higher stage tumor.

Q. There was a recent study released indicating that a protein, A1BG, is present in the urine of bladder  cancer patients, and may be a possible biomarker for bladder cancer. Can you provide more explanation and detail on this study?

A. Scientists from the University of Florida, Gainesville and the University of Michigan have recently developed a technique to profile selected proteins in voided urine specimens. The research team identified and evaluated 186 proteins. One protein of interest, alpha-1- beta-glycoprotein (A1BG), was found in the urine of patients with bladder cancer, but not in urine obtained from individuals without cancer. The function of the A1BG protein, initially discovered in 1986, is currently unknown. The results of this study are very preliminary, but further testing of the A1BG protein could lead to the development of a novel biomarker of bladder cancer.

Although the results are interesting, they are based on urine samples from only 10 research subjects. So, larger studies are needed to determine whether A1BG will be a clinically useful tool for patients. The scientific article is published in the Journal of Proteome Research. Volume 6, pages 2631-2639, July 6,  2007. The title is, “Bladder Cancer Associated Glycoprotein Signatures Revealed by Urinary Proteomic Profiling.” The study authors are Paweena Kreunin, Jia Zhao, Charles Rosser, Virginia Urquidi, David M. Lubman and Steve Goodison.