IDENTIFICATION OF H-RAS MUTATIONS IN URINE SEDIMENTS COMPLEMENTS CYTOLOGY IN THE DETECTION OF BLADDER

Background: Urinary cytology has long been used as a noninvasive scree n for the detection of urinary tract cancer but is limited by the gene ration of false positive and false negative results, More recently, mo lecular changes associated with urothelial neoplastic progression have been identified in DNA from urine sediments, demonstrating an alterna tive approach for identifying neoplastic change in the bladder, Purpos e: The purpose of this prospective study was to determine the value of detection of H-ras (also known as HRAS) mutations in urine sediment D NA as a clinical indicator of tumor presence, recurrence, and/or progr ession, Methods: Urine sediments were collected from 100 patients pres enting with bladder tumors, with follow-up samples collected from 19 p atients, DNA extracted from urine sediments was analyzed for changes i n exon 1 of the H-ras gene, using single-strand conformation polymorph ism (SSCP) analysis, A representative number of aberrant H-ras/SSCP mi grating bands were excised and sequenced to confirm the presence of a mutation, Human bladder specimens were obtained from patients (93 of t he 100 patients initially and 18 of the 19 patients studied by follow- up) and histologically evaluated for tumor content and grade, Results: Mutations in exon 1 of the H-ras gene were detected in urine sediment s from 44% (44 of 100) of the patients; concordant results were obtain ed by cytologic analysis, where 33% (31 of 93) of the patients display ed positive cytology, Analysis of the distribution of abnormalities wi th tumor grade revealed greater detection of low-grade (1-2) lesions u sing ras analysis (47%) compared with cytology (16%), In contrast, cyt ology was more effective in identifying the presence of carcinoma in s itu, Combined results from these two approaches substantially increase d the sensitivity of tumor detection, resulting in the identification of tumors in 60% of patients. Conclusions: Identification of W-ras mut ations in DNA from urine sediments facilitates the detection of low-gr ade bladder tumors and, in combination with cytology, increases the ov erall tumor detection from 33% to 60%, Preliminary results in patient follow-up suggest that detection of H-ras mutations may have some clin ical utility in detecting the presence of abnormal cells in the absenc e of an overt lesion following cytoscopy or positive cytology.