Test tells source of mystery cancers-researchers
WASHINGTON (Reuters) - A new test that analyzes genetic material can tell doctors the source of some mysterious cancers and perhaps help provide a short-cut for treating them, Israeli researchers reported on Sunday.
Israel-based Rosetta Genomics said its test, still not perfected, uses microRNAs, a type of genetic material that regulates genes and known to be involved in cancer.
Corporate researchers used the microRNAs to identify tumors that had spread in the body from unknown sources -- a type of cancer known as \"cancer of unknown primary\" or CUP.
Most cancers are named according to the place they first develop -- such as breast cancer or lung cancer or colon cancer. Even if these cancers spread, or metastasize, to the liver or brain or bones they are still identified by their primary origin.
\"But there is a group of patients who have tumors that appear in a metastatic site which, with the best imaging, you can't find a primary tumor,\" said Dr. Martin Raber of the University of Texas M.D. Anderson Cancer Center in Houston.
\"It either acquired the ability to metastasize so early in development that primary didn't develop. Or the primary never existed,\" added Raber, who specializes in such cancers and who was not involved in the research.
CUP accounts for 2 percent to 5 percent of cancers diagnosed in the United States each year, according to the American Society of Clinical Oncology.
Being able to identify the primary origin of a cancer is key to treating it, said Raber.
\"Today we have specific chemotherapies. We have therapies for colon cancer that don't seem to work in other settings,\" Raber said in a telephone interview. \"You can no longer design one regimen that captures all tumors.\"
One drug cannot even be used to treat all types of breast cancer or lung cancer, although many drugs work for a variety of cancers.
BIOMARKERS
Writing in the journal Nature Biotechnology, Nitzan Rosenfeld of Rosetta and colleagues said they used microRNAs as biomarkers to identify where in the body a tumor started.
After examining 400 samples of 22 different tumor tissues and metastases, they identified the source in two-thirds of cases, they reported.
\"Rosetta Genomics is currently developing a technology that will be the basis of a CUP diagnostic tests,\" the company said in a statement. They will submit it for Clinical Laboratory Improvement Amendments approval, a process overseen by the federal Centers for Medicare & Medicaid Services, later this year.
\"This research demonstrates the tremendous potential of microRNAs as effective biomarkers, and is a significant step towards the development of the first microRNA-based diagnostic tests,\" said Amir Avniel, president and chief executive officer of Rosetta Genomics.
Raber, who has informally spoken with Rosetta about using the test, said eventually such tests will become more refined.
\"At the end of the day as a doctor I don't really care if my unknown primary tumor patient had breast cancer, colon cancer or lung cancer,\" he said.
Companies are working to develop those tests, too.
http://www.reuters.com/article/healthNews/idUSN2328661520080323
华盛顿（路透社）—以色列的科学家们周日宣布，一种新的检测遗传物质的方法可以帮助科学家们发现一些神秘肿瘤的病原并且提供治疗这些肿瘤的简便方法。以色列Rosetta Genomics的负责人说：“这项检测手段目前还不够完善，它使用的是microRNAs（微小RNA病毒），一种调控基因表达并已知与一些肿瘤相关的遗传物质来进行的。”
研究者们使用这些microRNAs研究一种被称为“没有原发灶的肿瘤”即简写为CUP的肿瘤，这种肿瘤细胞在全身蔓延，但是却找不到肿瘤的原发灶。
大多数肿瘤的命名都是根据肿瘤的原发灶命名的，比如乳腺癌、肺癌、结肠癌。即使这些肿瘤转移到肝脏、大脑、骨骼，它们仍然是以原发灶部位来命名的。
位于休斯敦的德州大学Anderson癌症研究中心的Martin Raber博士说：“但是有一些病人的肿瘤首次发现时就是在转移的部位，而且即使用最精密的检查手段，也找不到肿瘤的原发灶。”
Martin Raber博士说的主要研究方向就是这种肿瘤，但他并没有参与这一试验，他补充说到：“这种肿瘤的形成需要肿瘤细胞具有在原发灶还没有完全形成的时候，或者原发灶根本就不存在的情况下拥有转移播散形成转移灶的能力。”
根据美国临床肿瘤学会的统计，CUP占到美国每年确诊的的肿瘤病例中的2%到5%。
Martin Raber博士说，明确肿瘤的原发灶是治疗的首要前提。
Martin Raber博士在电话采访中说：“目前我们拥有具有针对性的化疗药物，我们有专门针对结肠癌的化疗药物而这种药物对于其他肿瘤几乎不起什么作用，我们目前还不能制造一种对于所有肿瘤都有治疗效果的药物。”
甚至不同类型的乳腺癌或者结肠癌都不能用同一种药物治疗，即使许多药物都可以用于不同的肿瘤。
生物标记
Rosetta的Nitzan Rosenfeld以及他的同事在<the journal Nature Biotechnology>中写道，他们利用microRNAs作为生物学标记检测这些肿瘤的原发灶。
他们报道，在进行试验的22种不同肿瘤的组织以及转移部位的400个样本后，发现其中三分之二的有这些标记。
公司在一项声明中说：“Rosetta Genomics正在研发一种可以作为CUP诊断基础的检测手段。”他们将会在今年底把这项检测手段送交Clinical Laboratory Improvement Amendments（临床试验研究审核修正部门）以获得批准，这一过程将在联邦医学研究管理中心的监督下进行。
Rosetta Genomics总裁及首席执行官Amir Avniel说：“这项研究表明了microRNAs作为一种生物标记具有巨大的应用潜力，这项研究也是向着基于microRNAs的诊断性试验研究进程中一项巨大进步。”
曾经和Rosetta 讨论过这一检测手段的Raber博士也表示，这一检测手段将来会日趋完善。
他说：“未来的某一天，我将不会为一位CUP患者到底是乳腺癌还是结肠癌还是肺癌而担心了。” |
发表于 2008-4-4 07:23:01