Identification of metastasis suppressor genes for prostate cancer and establishment of genetic diagnosis and therapeutic system of prostate cancer.

鉴别前列腺癌进展的分子和细胞标志物将有助于发展前列腺癌亚分期的诊断方法。为了分离这些基因，我建立了一个大鼠前列腺癌系统。还检查了临床标本以确定分子标记。通过大鼠系统，我从8p21-22区分离出60kb的片段，其中包含转移抑制基因。这种转移抑制基因似乎没有被翻译成蛋白质。通过同样的方法，我已经证明了人类13号染色体含有转移抑制基因。我还研究了人类10号染色体抑制转移功能的机制。为了从前列腺癌标本中分离出均匀的癌组织，采用激光捕获显微解剖系统。从显微解剖组织中提取高质量的DNA并进行遗传分析。比较基因组杂交分析表明，2q、4q、6q、8p、13q、16q和18q经常丢失。8p和13q的缺失在pT3肿瘤中比在pT2肿瘤中更常见。13q的缺失在Gleason评分为7或更高的肿瘤中更为常见。6q缺失与生化复发有关。CGH分析确定的这些区域与之前PCR-LOH分析确定的区域基本相同。在本研究中，我也进行了常规的PCR-LOH分析，发现在晚期癌症病例中，12p13-12、2p16.3、2p12-cen、2q21.3和2q23.1-32.1位点经常丢失。笔者回顾了以往关于激素难治性前列腺癌发生发展的研究，发现主要有两种途径，雄激素受体（AR）依赖途径和AR独立途径。我还进行了临床研究，以便将上述分子数据应用于床边。

Identification of molecular and cellular markers for the progression of prostate cancer would be useful in developing diagnostic methods for substaging prostate cancers. To isolate such genes, I have established a rat prostate cancer system. Clinical specimens have been also examined to identify molecular markers.By using the rat system, I have isolated the 60-kb fragment from 8p21-22 region, which contains the metastasis suppressor gene. This metastasis suppressor gene did not seem to be translated to a protein. By using the same method, I have shown that human chromosome 13 contains metastasis suppressor gene(s). I have also examined the mechanism of metastasis-suppressing function by human chromosome 10.In order to isolate homogeneous cancerous tissue form prostate cancer specimens, laser capture microdissection system was utilized. DNA of high quality was extracted from the microdissected tissue and was genetically analyzed. Comparative genomic hybridization analysis demonstrated that frequent losses of 2q,4q,6q,8p,13q,16q,and 18q. Losses of 8p and 13q were observed more frequently in the pT3 tumors than pT2. A loss of 13q was observed more frequently in the tumors with Gleason score 7 or more. A loss of 6q was related with biochemical recurrence. These regions identified by the CGH analysis were essentially same as those previously identified by the PCR-LOH analysis. In this study, I have also performed the conventional PCR-LOH analysis and have found frequent losses at 12p13-12,2p16.3,2p12-cen,2q21.3,and 2q23.1-32.1 of the cases with advanced cancer.I have reviewed the previous studies on development of hormone-refractory prostate cancer, and found that there are two major pathways, androgen receptor (AR)-dependent pathway and AR-independent pathway. I have also performed clinical studies in order to apply the molecular data above to the bedside.