NOVEL P21(WAF1 CIP1) MUTATIONS IN SUPERFICIAL AND INVASIVE TRANSITIONAL-CELL CARCINOMAS/

Alterations in the p53 gene are a predominant component in the develop ment of transitional cell carcinoma (TCC), but the particular pathways distal to p53 alterations which contribute to urothelial transformati on are not defined, Here, the p21(WAF1/CIP1) gene, a p53 inducible and p53 independent gene product, was studied in TCC, p21(WAF1/CIP1) expr ession was measured by quantitative reverse transcriptase-polymerase c hain reaction (RT-PCR) from five cell lines and 28 tumor specimens (14 superficial, 14 muscle invasive), This was expressed as a ratio of th e gene product to L7, a ribosomal housekeeping gene, In addition, exon s 4 through 8 of the p53 gene as well as exon 2 of the p21(WAF1/CIP1) gene were assayed for mutations by polymerase chain reaction/ single s tranded conformation polymorphism analysis (PCR/SSCP), Candidate mutat ions were verified by sequencing, p21(WAF1/CIP1)/L7 expression was sig nificantly decreased in invasive lesions compared to superficial lesio ns (P<0.002), p53 mutations were detected by PCR/SSCP in seven tumors [25%] (one superficial, six invasive) and p21(WAF1/CIP1)/L7 expression was significantly decreased in all tumors that had p53 mutations (P<0 .007), PCR/SSCP analysis of exon 2 in p21(WAF1/CIP1) detected band in tumor specimens (two superficial, two invasive), which sequencing and comparison to autologous normal matched DNA revealed as novel mutation s.