RESUMO
Objecfive Most prostate cancer contains two or more widely separate turnors.To study the origin of prostate cancer based on the analysis of microsatellite alteration in separate tumors from the same prostate.Methods A polymerase chain reaction (PCR) was used to examine the allelic loss pattern of 4 microsatellite polymorphic markers on chromosome 8p (D8S133,D8S136,D8S137) and 17q (D17S855) in multifocal tumors of prostate from 19 patients.DNA samples were obtained from different regions of distinctly separate tumors on single case using microdissection technique.Results The overall frequence of LOH at D8S133,D8S136,D8S137 and D17S855 for all informative cases was 74%,38%,86% and 46%respectively in 40 separate tumors of prostate from 19 patients.The pattern of allelic loss was not identical in 15 of 18 (83%) informative cases. It showed that the different regions of prostate cancer were independent origin respectively.Discordant pattern of histology was observe in distantly separate regions.whereas the same allele was consistently lost in samples from different regions of the same tumor in 3 cases. Condusion Current data supports independent origin of multiple tumors in most prostate cancer patients.