Genomic instability of microsatellite repeats in prostate cancer: relationship to clinicopathological variables.

Sixty-six patients with prostatic adenocarcinoma were screened for somatic instability at 8 microsatellite marker loci on 5 chromosomes. Differences in unrelated microsatellites for tumor and normal DNA were detected in 13 (19.7%) patients. Only extraglandular spread (nodal involvement and distant metastasis) was found to show significant association with somatic instability after controlling for other clinicopathological variables (P < 0.05). Microsatellite instability may possibly occur during the early stages of neoplastic transformation in a subset of prostate cancer rather than as a late event. This may be related to a phenotype with growth advantage. The frequency of this mutator phenotype is much higher in the United States than Japan, reflecting racial differences in the molecular tumorigenesis of this malignancy.