EXPRESSION OF CD44 SPLICE VARIANTS IN HUMAN TRANSITIONAL-CELL CARCINOMA

The CD44 cell adhesion molecule is a surface glycoprotein mainly expre ssed in lymphoid tissues. Recently, abnormal variants of CD44 includin g alternatively-spliced large molecular variants, have been reported i n many neoplastic tissues. We studied the variation in the size of CD4 4 molecules in 25 transitional eel carcinomas and 11 normal transition al epithelial tissues, using the reverse transcriptase-polymerase chai n reaction (RT-PCR) followed by electrophoresis and Southern blot hybr idization. Whereas 23 of 25 (92.0%) tumor tissues expressed CD44 splic e variants with targe molecular size, only 1 of 11 (9.1%) normal tissu es expressed the abnormal variants. Urine sediments from 5 of 7 (71.4% ) patients also was positive for the CD44 splice variants. CD44 splice variants are increased markedly in human transitional cell carcinoma, in conclusion, detection of CD44 splice variants using the RT-PCR, wh ich is a convenient molecular biological technique, may be useful in c ombination with other diagnostic methods such as cytology, flow cytome try, and tumor antigens.