Genetic instability in incidentally discovered and advanced prostate cancer

Abstract

Objective: To investigate the frequency of microsatellite instability, a marker for genetic instability, in incidental and advanced prostate cancers, and to determine the role and prognostic importance of genetic instability in prostate carcinogenesis.

Patients and methods: Microsatellite analysis was performed on 72 prostate cancers, of which 26 were incidentally discovered at transurethral prostatectomy (TURP) for benign disease. They were staged and graded 1-3 according to glandular differentiation. Fresh prostatic tissue was obtained at TURP performed for bladder outlet obstruction, from 43 patients (median age 73 years, range 55-88), with tissue from the remaining 29 (median age 75, range 53-83) patients obtained from pathology archives, having been originally collected at TURP between 1969 and 1986.

Results: Instability was detected in 14 (19%) cancers overall, in eight (31%) of 26 incidental tumours and in six (13%) of 46 clinically apparent tumours. These differences were not statistically different (2P=0.1). The time to progression and survival were similar between men with tumours showing instability and those with no instability.

Conclusion: These data suggest that genetic instability is an early event in prostate carcinogenesis, but does not appear to influence prognosis.