[Mapping of a deletion interval on 8p21-22 in prostate cancer by gene dosage PCR]

Various microsatellite and CGH studies in prostate cancer identify deletions on the short arm of chromosome 8 especially at band 8p21-22 searching for unknown putative tumor suppressor genes. By means of microsatellite markers several candidate genes were detected which may play different roles in early prostate cancer progression. We established a quantitative gene dosage PCR based on the real time PCR method serving the purpose of genomic fine mapping. Therefore we used 10 Assays-on Demand (ABI) for the detection of deletions located between and nearby the microsatellite markers D8S258 and NEFL spanning a genomic region of approximate 7 mbp. Comparative immunohistochemical analysis from tissue micro arrays (TMA) of 1122 independent cases followed. We were able to detect three clearly separated deletion intervals on 8p21-22. One on LZTS1, second on NEFL and third a deletion hot spot on LOXL2, which was affected in 72% of all investigated cases. Our comparative immunohistochemical TMA based studies demonstrate that LOXL2 is nearly lost in most prostate cancer tissues. LOXL2 catalyze the crosslinking of collagen and elastin in the extracellular matrix and it has been assumed that it is involved in tumor suppression and cell adhesion. LOXL2 is frequently expressed in proliferating tissues and shows a high expression in benign prostate tissue too. In prostate cancer the expression is positive correlated with the MIB1-score.