[Relationship between the abnormal expression of CD44 gene and bladder cancer]

Reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot hybridization were used to detect exon V6-containing isoforms of CD44 gene in 42 surgical bladder specimens (20 cases of bladder cancer, 10 cases of corresponding normal bladder tissue, 8 non-neoplastic bladder tissue from the benign prostatic hyperplasia, and 4 cystitis). All samples of bladder cancer tissue showed over-expression of many abnormal alternatively-spliced products containing transcripts from exon V6 of the CD44 gene except those from 22 non-neoplastic tissue. Furthermore, the band pattern permitted differentiation between the 2 cases of metastatic bladder tumors and the 18 cases of non metastatic tissue. Our results suggest that there is a remarkable relationship between the abnormal CD44 gene expression (inappropriate splicing and overexpression) and malignant phenotype and metastasis of bladder cancer. The CD44 splice variants may prove to be a more ideal tumor marker for the early diagnosis of bladder cancer and for the early detection of metastatic potential in surgical biopsy specimens, which deserves further evaluation.