Importance of chromosome 8 gain and M-MYC gene amplification in prognosis of prostate cancer

2, ABSTRACT The clinical course of the prostate cancer is highy complex and genetic factors underlying tumorigenesis are poorly understood. Recently, cytogenetic and molecular biological studies have identified the band 8q24, where C-MYC gene located is commonly amplified in prostate cancer, especially in advanced and recurrent ones. Fluorescence in situ hybridization (FISH) technique of interphase cells allows the detection of chromosomal alterations which are diffucult to evaluate using conventional cytogenetic methods. We examined a total of 24 speciemens, including 9 adenocarcinoma, 6 prostatic intraepithelial neoplasi (PIN) and benign prostatic hyperplasia (BPH) by FISH. Interphase-FISH method was performed with locus specific probe for C-MYC and centromeric probe for chromosomes 8. Gain of chromosome 8 identified in 88.8% of adenocarcinomas was associated in metastatic prostate cancer (p<0.04). C-MYC gen amplification was found in 11.1% of adenocarcinoma, but never detected cases of PIN and BPH. The most freguent anomaly in PIN and carcinoma was a gain of chromosome 8, and the presence of this anomaly strongly correlated with high Gleason Score. We believe that basic mechanism in overexpression of C-MYC gene may not be amplification. Our results indicate that basic mechanism of C-MYC gene overexpression may be gain of simple chromosome 8 or gain of "8q". Our results agree with findings of other authors that PIN is probably a procurser of carcinoma- Key words: prostate cancer, gene amplification, FISH, C-MYC