Response

Extract

Dr. See has pointed out that Xu and See (1) published a paper on cytokine regulation of plasminogen activatorrelated proteins in which the expression of the messenger RNA for urinary plasminogen activator receptor in transitional cell carcinoma cell lines was reported. Omission of Drs. Xu and See's work in our report (2) was by no means deliberate. We were unaware of their article, which was not found on a standard MEDLINE subject search at the time that our manuscript was submitted. For completeness, we also add that we were unaware that Drs. Xu and See had presented these same data at the annual meeting of the American Urological Association in April 1995, which were published as an abstract in the Journal of Urology (3).

Dr. See has cited only a part of the sentence from our report, and we believe that it lost some of its meaning when taken out of context. The full sentence reads, “To our knowledge, this is the first study demonstrating that bladder tumor cells express the urokinase receptor and that both receptor expression and urokinase expression are required for bladder tumor cell invasion In vitro.” Those who have read our report realize that the paper primarily emphasizes the functional relationship between concomitant expression of urokinase and its receptor and the ability of bladder cancer cells to invade an artificial basement membrane. The importance of our work is in the functional significance of the receptor, not merely its presence. A preliminary report of our work on the detection of the urokinase receptor in human bladder cancer was also published in an abstract form and presented at the annual meeting of the American Association for Cancer Research in March 1995 (4).