Short Communication Molecular Cytogenetic Analysis of Prostatic Adenocarcinomas from Screening Studies Early Cancers May Contain Aggressive Genetic Features

small (total tumor volume (Tv) < 0.5 ml) carcinomas and 23 intermediate (Tv between 0.5-1.0 ml) tumors. These samples were compared with a set of 16 locally advanced, large (Tv > 2.0 ml) tumor samples, not derived from the European Randomized Study of Screening for Prostate Cancer. Chromosome arms that frequently (ie, >15%) showed loss in the small tumors included 13q (31%), 6q (23%), and Y (15%), whereas frequent (ie, >15%) gain was seen of 20q (15%). In the intermediate cancers, loss was detected of 8p (35%), 16q (30%), 5q (26%), Y (22%), 6q, and 18q (both 17%). No consistent gains were found in this group. In the large tumors, loss was seen of 13q (69%), 8p (50%), 5q, 6q (both 31%), and Y (15%). Gains were observed of 8q (37%), 3q (25%), 7p, 7q, 9q, and Xq (all 19%). Comparison of these early, localized tumors with large adenocarcinomas showed a significant increase in the number of aberrant chro- mosomes per case (R s 5 0.36, P 5 0.009). The same was true for the number of lost or gained chromo- somes per case (R s 5 0.27, P 5 0.05; Rs 5 0.48, respectively; P < 0.001). Interestingly, chromosomal alterations that were found in previous studies to be potential biomarkers for tumor aggressiveness, ie, gain of 7pq and/or 8q, were already distinguished in the small and intermediate cancers. In conclusion, our data show that chromosomal losses, more specif- ically of 6q and 13q, are early events in prostatic tumorigenesis, whereas chromosomal gains, espe- cially of 8q, appear to be late events in prostatic tumor development. Finally, early localized tumors, as detected by screening programs, harbor cancers with aggressive genetic characteristics. (Am J Pathol 2001, 158:399 - 406)