LOSS OF HETEROZYGOSITY OF THE RETINOBLASTOMA AND ADENOMATOUS POLYPOSIS SUSCEPTIBILITY GENE LOCI AND IN CHROMOSOMES 10P, 10Q AND 16Q IN HUMAN PROSTATE-CANCER

Objective To examine prostate tumours for losses of known or suspected tumour suppressor genes to determine some of the important events in the genesis of this common cancer. Materials and methods Paired tumour and blood samples were obtained from 21 patients who underwent transu rethral resection of malignant prostate glands for urinary outflow obs truction. Paired tumour and normal tissue (leucocytes) DNA was extract ed and examined for possible losses of several known or suspected tumo ur suppressor genes, using restriction fragment length polymorphism te chniques to detect loss of heterozygosity. Results Deletions of the re tinoblastoma susceptibility gene (RB1) locus were found in six of nine informative cases using two intragenic probes (p68RS2.0 and p123ml.8) . The locus related to the familial adenomatous polyposis susceptibili ty (APC) gene demonstrated loss of heterozygosity in three of seven in formative cases using the EF5.44 probe. Losses were also noted in loci on chromosome 10p in four of 19 informative cases (probe cTBQ7), chro mosome 10q in eight out of 19 informative cases (probes EFD75 and D10S 90) and in 16q in three of 17 informative cases (probe D16S7). Conclus ion These finding suggest that losses of the RB1 and APC tumour suppre ssor genes and suspected tumour suppressor genes on 10p, 10q and 16q m ay be important events in the genesis of prostatic tumours.