HIGH-LEVEL EXPRESSION OF THE CD44 VARIANT SHARING EXON V10 IN RENAL-CANCER

To examine whether renal cell carcinoma displays altered CD44 expressi on we performed reverse transcription-polymerase chain reaction (RT-PC R) analysis of CD44 in 38 specimens from renal cancer, normal kidney a nd metastases of 19 patients and 6 renal cancer cell lines. To detect the CD44 variants, we utilized the RT-PCR Southern blot method. One ou t of 19 (5.3%) renal cancer specimens expressed a larger molecular wei ght band than 1 kb by RT-PCR analysis, in contrast to previous finding s in colon and breast cancer. The band patterns in RT-PCR were differe nt in 14/17 (82.4%) cases between normal kidney and tumors, and a band of about 700 bp was especially marked in 12/17 (70.6%) tumor specimen s and 4/6 (66.7%) cell lines. By cloning and sequencing of the 700 bp band, we found that this variant is identical to the CD44 variant shar ing only exon v10. Examination by Northern blot analysis has revealed that all tumors express a higher level of CD44 mRNA than paired normal kidneys. These findings suggested that the CD44 variants sharing exon v10 play some role in renal cancer.