EPHB2基因突变：促发前列腺癌的基因

一个国际研究小组设计了一种检测方法来筛查和鉴别肿瘤生长抑制基因。这种检测方法使得发现新的癌症基因（当受到损害的时候会促发前列腺癌）成为可能。运用这种新技术，可以在大约25,000个人类基因中鉴别出肿瘤抑制基因，并且显著加快研究进程。运用新方法在单个实验室中就可以筛查上千个基因。

这种检测方法的高效率是因为联合使用了两种筛查方法：无义介导的mRNA衰减（nonsense-mediated mRNA decay，NMD）基因芯片技术被用于筛查突变基因，而比较基因杂交（comparative genomic hybridisation，CGH）基因芯片技术被用于筛查同一样本中DNA拷贝丢失的数量。通过联合检测研究人员能够有效地查明在癌细胞中功能失活的基因。

运用这种方法研究人员在EPHB2基因中发现了异常。该基因编码一种细胞膜受体，这种受体在细胞内信息传递中起作用，同时也在细胞分化、细胞活动性、维持正常组织结构中起作用。EPHB2基因功能的异常会导致相应的组织异常，并促进癌细胞的增殖与转移。

研究人员发现在8％的前列腺癌患者中出现EPHB2突变，尤其是在转移性癌患者中。这个发现有望促进前列腺癌新治疗方法的发展。研究人员瞄准进一步改善NMD-CGH基因芯片技术，并将之应用于发现前列腺癌以及其它癌症的尚未被发现的肿瘤抑制基因。

该研究在芬兰VTT的医学生物技术系中继续进行，同时与美国翻译基因组学研究院（the Translational Genomics Research institute）的一个国际研究队伍紧密合作。

Identified: Gene that Promotes Prostate Cancer

An international research team has developed a method for the screening and identification of tumour growth-suppressing genes. The method enabled the discovery of a new cancer gene, which, when damaged, may promote prostate cancer.

With the new technique, it is possible to identify potential tumour-suppressor genes from among the approximately 25,000 human genes and accelerate research significantly. The new method allows the screening of thousands of genes in a single laboratory experiment.

The effectiveness of the method is due to the combination of two screening methods: the NMD(nonsense-mediated mRNA decay) microarray technique is used to screen for mutated genes, while the CGH (comparative genomic hybridisation) microarray technique is used to screen for DNA copy number losses from the same sample. By combining these findings researchers can efficiently pinpoint those genes whose function has failed in cancer cells.

Using this method the researchers found errors in the EPHB2 gene. The gene encodes a cell membrane receptor, which has a role in the intracellular communication, and is required for cell differentiation, cell mobility and maintenance of correct tissue structure. A defect in the EPHB2 gene function may thus cause tissue dysorganisation and promote the proliferation and metastatis of cancer cells.

Researchers found mutations in EPHB2 gene in 8 per cent of prostate cancer patients, particularly in the metastatic tumours. The discovery is hoped to facilitate the development of novel therapeutics for prostate cancer. The researches aim to develop the NMD-CGH microarray method  further and apply it for new tumour-suppressor gene discovery approaches in prostate cancer and other cancer types.

The research was continued in Finland at VTT in the Medical Biotechnology Department, in collaboration with a research team at the Translational Genomics Research institute in the US.