MAPPING OF REGIONS OF PHYSICAL DELETION ON CHROMOSOME 16Q IN PROSTATE-CANCER CELLS BY FLUORESCENCE IN-SITU HYBRIDIZATION (FISH)

Recent evidence suggests that a tumor suppressor gene important in the progression of prostatic carcinoma may reside on chromosome 16q. The exact location and identity of this gene are unknown. We used fluorescence in situ hybridization in a novel manner to define more clearly the location of this gene. Region-specific chromosome 16 cosmid contig probes were hybridized directly to interphase prostatic carcinoma nuclei in order to measure physical deletion of chromosomal loci. Fifteen of 30 tumors (50%) showed evidence of physical deletion of 16q24. Other probes were used to test for regions of chromosome 16 deletions in the same specimens, and a map showing a region of common deletion was created. This map showed the proximal terminus of the region of common deletion to be located distal to 16q23.1. These data correlate well with loss of heterozygosity data in the literature and provide further evidence for the presence of a prostatic carcinoma tumor suppressor gene on chromosome 16q.