EXPRESSION OF CD44 SPLICE VARIANTS IN BLADDER CANCER

Abstract

Recently, it was noted that CD44 participates in a wide variety of cell-cell or cell-matrix interactions including tumor metastasis and the altered expression of CD44 splice variants is helpful in the diagnosis of colon and breast cancer. The purpose of the study was to investigate altered expression of CD44 in bladder cancer. Thirty-three surgical specimens of 22 patients and seven bladder cancer cell-lines were analyzed by various methods including RT-PCR-Southern blotting. Northern blotting, and flow-cytometric analysis. In RT-PCR analysis, the hematopoietic variant and numerous additional variants were detected in all cell-lines and almost all surgical specimens. In three out of seven cell-lines of bladder cancer (42.9%), especially numerous larger bands (ladder pattern) were detected using RT-PCR. These three cell-lines expressed a smaller quantity of CD44 mRNAs and CD44 molecules than the other four cell-lines. In eighteen out of 22 (81.8%) bladder cancer specimens, we detected larger variants that exceed 1500 base pairs, compared with the detection in four out of eleven (36.4%) visually normal mucosa specimens (P < 0.05). However, there was no correlation between the expression of the larger variants and clinicopathological features. The quantitative and qualitative change of CD44 variants were demonstrated in bladder cancer.