Purpose: We determined if characteristic chromosomal anomalies exist within the primary tumors and lymph node metastases in patients with stage D1 prostate cancer, and compared the patterns of chromosomal alterations between primary tumors and nodal metastases.
Materials and methods: Fluorescence in situ hybridization analysis using peri-centromeric probes for chromosomes 6, 7, 8, 17, X and Y was performed on 5 mu. sections from paraffin embedded tissue blocks obtained from 23 consecutive patients who underwent radical prostatectomy and bilateral pelvic lymphadenectomy in 1990 for stage D1 prostate cancer.
Results: The dominant focus of primary tumor was compared to matched nodal metastases in 12 cases. Five of 12 primary tumor foci (41.7%) had similar chromosomal gains and the same fluorescence in situ hybridization ploidy result as the corresponding nodal metastases. Chromosomes 7 and X (73.2% of cases) were most frequently gained in the primary tumors, and chromosomes X and Y (81.2% of cases) were most frequently gained in the metastases. No primary tumor or metastasis demonstrated chromosomal loss. Three of 19 primary tumors (15.7%) were diploid, while 16 of 19 (84.3%) were nondiploid. Chromosomal aneusomy was inversely correlated with increasing Gleason summary score.
Conclusions: These data indicate that the dominant primary tumor foci may not give rise to nodal metastases, gains of chromosomes 7, X and Y may be associated with metastatic behavior, and patients with stage D1 disease have a greater rate of aneuploidy than those with lower stage cancer.