Detection of LOH of the RB1 Gene in Bladder Cancers by PCR-RFLP

Objectives: Retinoblastoma (RB1) gene involves in retinoblastoma, osteosarcoma, bladder, prostate, lung, breast carcinomas, and soft tissue sarcomas. Loss of heterozygosity (LOH) is the most common mutation of the gene. Methods: Xba I polymorphism in intron 17 of the gene was used to detect LOH in 20 bladder cancer patients. A cystitis and an osteosarcoma were used as control. LOH was investigated in three different kinds of samples (blood, paraffin-embedded tissue and fresh tissue) belonging to the same patients, and 20 blood samples, 20 paraffin-embedded tissue samples and 16 fresh tissue samples were obtained from 20 cancer patients. Results: None of the 20 blood samples showed LOH. Eleven out of 20 paraffin-embedded bladder tissues were amplified, 3 of them homozygous and all 8 informative paraffin-embedded tissues showed LOH. Five out of 16 fresh tumor tissues obtained were amplified, in 1 the fresh tissue was normal, 1 fresh tissue showed LOH and 3 were not digested by Xba I. Conclusion: The results of the study have suggested that detection of LOH of the RB1 gene by PCR-RFLP can be a good adjunctive test for evaluation of the bladder cancer.