Molecular Genetics of Prostate Cancer

前列腺癌的分子遗传学

• 批准号: 6558695
• 负责人: William Marston Linehan
• 金额: --
• 依托单位: DIVISION OF CLINICAL SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6558695
• 关键词: biopsy; carcinogenesis; cell line; cellular oncology; chromosome deletion; clinical research; dissection; genetic library; genetic mapping; genetic markers; human genetic material tag; human subject; lasers; male; metastasis; molecular oncology; neoplasm /cancer genetics; neoplastic process; nucleic acid sequence; prostate neoplasms; prostate surgery

In order to investigate the genetic events associated with the initiation and progression of prostate cancer, scientists from the Urologic Oncology Branch (UOB) and the Laboratory of Pathology (LOP) at the NCI have made use of a number of innovative methodologies centered around the procurement of highly purified prostatic cancer cells from heterogeneous tissue. Novel microdissection techniques which allow such procurement were developed in the LOP; the most recent such technique involving laser capture of cells greatly increased the speed and purity of dissection.Chromosomal deletions are often found in the vicinity of genes that protect cells from becoming cancerous. Using DNA prepared from 99 microdissected tumors, scientists in the UOB analyzed 45 genetic markers spanning a number of chromosomal regions that had been previously implicated in prostate carcinogenesis. The highest rate of deletion was observed on human chromosome 8, where the overall rate of loss was 86%. Approximately 80% of the cancers shared a common region of deletion within chromosome 8 (8p21). This region also overlaps a region recently identified as a locus for familial breast cancer.Human prostate cancer is thought to progress through a pre-malignant phase called prostatic intraepithelial neoplasia (PIN) prior to evolving into invasive cancer. In the region of chromosome 8 commonly deleted in cancer, deletions were also found in 63% of PIN lesions. This result suggests that abnormalities on 8p21 may be associated with early stages of prostate cancer development.A physical map of the region is currently being constructed in the UOB, and the UOB and LOP teams have begun analyzing candidate genes which reside in this area.Scientists in the LOP found that microdissected prostate samples also yielded good quality RNA, which has allowed them and the UOB team to analyze differences in gene expression in normal vs. tumor tissue. In addition to looking directly for expression of various genes in specific cell populations, libraries containing expressed genetic sequences were constructed as part of the multidisciplinary Cancer Genome Anatomy Project (CGAP). Twenty prostate libraries were constructed covering a spectrum of biology from normal to pre-malignant to localized and metastatic cancer. These libraries were sequenced at the Genome Sequencing Center at Washington University and found to exhibit high quality representation of both known and heretofore undiscovered genes. Data from large scale library sequencing allows for identification and comparison of genes expressed at distinct stages of tumor progression. The information generated is being used to guide the selection of candidate genes which map to 8p21.Finally, in order to expand upon the available resources for examination of prostate cancer in living cells, cell lines were established by scientists from the UOB and the Surgery Branch. The lines were generated from tissue from nine patients who underwent radical prostatectomy and four patients with advanced prostate cancer who underwent biopsy at the NCI. These lines will allow for future in vitro growth studies.

为了研究与前列腺癌发生和发展相关的遗传事件，来自国家癌症研究所泌尿外科肿瘤科(UOB)和病理实验室(LOP)的科学家们利用了许多创新的方法，这些方法以从异种组织中获取高纯度的前列腺癌细胞为中心。LOP开发了允许这种获取的新型显微切割技术；最新的这种涉及激光捕获细胞的技术极大地提高了切割的速度和纯度。染色体缺失经常发现在保护细胞免受癌变的基因附近。使用从99个显微解剖的肿瘤中提取的DNA，UOB的科学家们分析了45个遗传标记，这些标记跨越了一些以前被认为与前列腺癌发生有关的染色体区域。在人类8号染色体上观察到的缺失率最高，总缺失率为86%。大约80%的癌症共有8号染色体(8p21)内的共同缺失区域。该区域还与最近被确定为家族性乳腺癌的区域重叠。人类前列腺癌被认为在演变为浸润性癌症之前经历了称为前列腺上皮内瘤变(PIN)的癌前阶段。在癌中常见的8号染色体缺失区域，63%的PIN病变也存在缺失。这一结果表明，8p21上的异常可能与前列腺癌发展的早期阶段有关。该区域的物理地图目前正在UOB中构建，UOB和LOP团队已经开始分析该区域的候选基因。LOP的科学家发现，显微切割的前列腺样本也产生了高质量的RNA，这使得他们和UOB团队能够分析正常组织和肿瘤组织中基因表达的差异。除了直接寻找特定细胞群体中各种基因的表达外，作为多学科癌症基因组解剖计划(CGAP)的一部分，还构建了包含表达的基因序列的文库。构建了20个前列腺癌文库，涵盖了从正常到癌前病变到局部和转移癌的各种生物学特征。这些文库在华盛顿大学的基因组测序中心进行了测序，发现它们展示了已知和迄今未发现的基因的高质量代表。来自大规模文库测序的数据允许识别和比较在肿瘤进展的不同阶段表达的基因。产生的信息被用来指导选择映射到8p21的候选基因。最后，为了扩大可用于检查活细胞中前列腺癌的可用资源，来自大华大学和外科分部的科学家建立了细胞系。这些线条是从9名接受根治性前列腺癌切除术的患者和4名在NCI接受活检的晚期前列腺癌患者的组织中产生的。这些品系将为未来的体外生长研究奠定基础。