S-PHASE FRACTION RELATED TO PROGNOSIS IN LOCALIZED PROSTATE-CANCER - NO SPECIFIC SIGNIFICANCE OF CHROMOSOME-7 GAIN OR DELETION OF 7Q31.1

A flow-cytometric (FCM) and fluorescence in situ hybridization (FISH) study was performed in 153 patients with clinically localised prostate cancer (PC) to evaluate retrospectively the prognostic significance o f DNA ploidy, S-phase fraction (SPF) and chromosome 7 copy number. Del etions in 7q31.1 were analysed in a subset of 26 tumours. The mean fol low-up time was 6 years (range 4-16 years). Twelve cases of benign pro static hyperplasia (BPH) were studied as a control. Chromosome 7 enume ration and deletion studies were conducted using the cu-satellite D7ZI probe and a cosmid probe specific for the marker D7S522 on 7q31.1. Hi gher SPF was associated with shorter overall survival and shorter time to local progression and metastasis. Near diploid (DNA index 1.05-1.2 0) cases had a lower frequency of metastases and lower Gleason scores than aneuploid cases. Increased absolute chromosome 7 copy number (cen tromere count) was associated with higher Gleason score, higher SPF an d shorter local progression-free and prostate cancer survival. Absolut e chromosome 7 copy number was concordant with FCM DNA ploidy in the m ajority (75%) of cases. Relative gain or loss of chromosome 7 (centrom ere counts compared to ploidy) was infrequent, and no correlation was found with clinical parameters. Deletions in 7q31.1 were infrequent. O ur results indicate that in localised PC (i) SPF is a prognostic: fact or, (ii) absolute chromosome 7 copy number is concordant with the ploi dy status of the tumour (relative gain or loss of chromosome 7 is infr equent and has no independent prognostic value) and (iii) the frequenc y of deletions in 7q31.1 is low and not correlated with clinical outco me. (C) 1998 Wiley-Liss, Inc.