Fluorescence in situ hybridization evaluation of c-myc and androgen receptor gene amplification and chromosomal anomalies in prostate cancer in Japanese patients.

Abstract

Oncogene amplification and chromosomal anomalies are found in many solid tumors and are often associated with aggressiveness of cancer. We evaluated the frequency and the association of c-myc and androgen receptor (AR) gene amplification and gain of chromosome 8 or X in prostate cancer in Japanese patients. We examined a total of 42 prostate cancer specimens, using fluorescence in situ hybridization (FISH). Dual-labeling hybridization with a directly labeled centromere probe for chromosome 8 or X together with a probe for the c-myc or AR locus was performed. Gain of chromosome 8 was identified in 54.8% of specimens and was associated with Gleason sum and nuclear anaplasia in untreated prostate cancers. c-myc gene amplification was found in 14.3% of specimens. Gain of chromosome X was identified in 42.9% of specimens. AR gene amplification was detected in 0 of 37 untreated prostate cancers, but in 1 of 5 hormone-refractory prostate cancers. Our results suggest that c-myc and AR gene amplification and gain of chromosome 8 or X may be associated with the development and progression of prostate cancers. These results obtained in Japanese cases are consistent with the results observed in prostate cancer in Western countries.