NUMERIC ALTERATIONS IN CHROMOSOME-7 AND CHROMOSOME-8 DETECTED BY FLUORESCENT-IN-SITU-HYBRIDIZATION CORRELATE WITH HIGH-GRADE LOCALIZED PROSTATE-CANCER

Objective: To compare the ability of flow cytometry (FCM) and fluoresc ent in situ hybridization (FISH), using a small set of 4 enumeration c hromosome probes to detect aneuploidy in prostate tumors, and to corre late it with histological grade and pathological stage. Methods: Among 28 suitable cases, 21 could be analyzed by FISH and FCM techniques. D NA centromeric probes were used in FISH analysis to enumerate chromoso mes 7, 8, 10 and 12. Results: (a) Of the 21 cases studied by FISH, 5 w ere diploid, 14 aneuploid and 2 were tetraploid. When studied by FCM, these tumors were: 14 diploid, 6 aneuploid, and 1 tetraploid. FISH pro ved to have a higher ability for detecting DNA aneuploidy than FCM whi le been equally specific, since all tumors aneuploid by FCM were also found to be aneuploid by FISH. (b) Of the 14 aneuploid tumors, 12 were of high histological grade, while only 2 of the 7 nonaneuploid were o f high grade. A statistically significant association was observed bet ween high histological grade and FISH aneuploidy (p = 0.033). (c) All the aneuploid tumors showed chromosome 7 and/or 8 aneusomy. Trisomy 7 and monosomy 8 were the most frequent alterations present in 56 and 42 % of the aneuploid tumors, respectively. Conclusion: FISH analysis of chromosome 7 and 8 alterations proved to be more sensitive than FCM in the detection of aneuploid prostate tumors. This aneuploidy was signi ficantly associated with a poor pathological prognosis.