Screening of human bladder tumors and urine sediments for the presence of H-ras mutations.

A series of 111 human bladder tumors were screened using oligonucleotide mutant specific probes, restriction enzyme analysis and single-stranded confirmation polymorphism (SSCP) for the presence of H-ras activation events. Thirty-three tumors were found to harbor H-ras mutations where a glycine to valine (G-->T) change in codon 12 was the most common point mutation recorded (26 tumors). Additional mutations involved glycine to cysteine at codon 13 (2 tumors) and glutamine to arginine/lysine/leucine at codon 61 (3/1/1 tumors, respectively). Ambiguous signals recorded with oligonucleotide probes were further analyzed using SSCP analysis revealing the presence of H-ras mutations in restricted regions of some tumors. The apparent sensitivity of SSCP enabled us to extend this study to DNA isolated from urine sediments where 4 of the 9 patients studied showed representation of mutant H-ras. Our study demonstrates a sensitive, non-invasive assay for the screening of urine-borne cells, with no requirement for prior knowledge of the mutational change at the H-ras locus.