英国剑桥大学临床医学院Tony Green教授
《肿瘤瞭望》:请您谈一谈对本届大会的总体印象?
Green教授:本届大会非常精彩,学术委员会安排到位,邀请了大量讲者,共有210个单独的学术会议,超过10000个代表参加会议。不仅如此,维也纳的天气怡人,风景秀美,这几天因有众多科学信息及学术交流而变得熠熠生辉。因此,对我来说,这是一个令人愉快的会议。
It has been wonderful. The Scientific Program Committee have done a great job inviting a wide range of speakers. There have been around 210 separate scientific sessions for about 10000 delegates. Not only all that, but they organized the weather as well, because that has been really beautiful. It has been a wonderful few days in Vienna with lots of good science and good interaction. So, for me, a very enjoyable meeting.
《肿瘤瞭望》:我们都知道您主要做造血干细胞与恶性血液病的机制研究,尤其是JAK/STAT 信号通路在其中的作用。请您向我们介绍一下您有哪些最新的发现,尤其是在骨髓增殖性肿瘤(MPN)方面的转化应用?
Green教授:距离JAK2突变首次报道已有10年,随着时间的推移,骨髓增殖性肿瘤已从“灰姑娘”变成一个炙手可热的领域,这不仅仅是对骨髓增殖性肿瘤患者福音,也是研究者们取得广泛共识的结果。我们现在知道JAK2突变在很多骨髓增殖性肿瘤患者中存在。某些亚型患者中的12号外显子还存在其他类型的突变,这些患者表现的和特发性红细胞增多症相似,但是事实上是真性红细胞增多症。
JAK2突变产生两方面的重要影响。首先,也可能是最显著的,是对诊断的影响。目前,欧洲已推荐其作为很多血液疾病的一线检测指标,例如在高血红蛋白患者中。与其进行一系列复杂检测来明确真性红细胞增多症的诊断,我们需要只是血细胞计数,显示血红蛋白水平高,分子检测出JAK2突变。这项检测非常简单,对诊断具有革命性的意义。同样的,其对原发性血小板增多症(ET)也有显著影响。当然在ET中,大约有一般的患者缺少JAK2突变。因此,最新的变化就是Gary Gilliland和Ross Levine发现了MPL突变,然后就是最近的我们和Robert Kralovics研究组发现的CALR突变。目前,我们知道这些突变约和80%的ET患者的发病相关。因此,目前诊断是更有力的过程。
第二个重要影响当然是在治疗方面。JAK2抑制物在2010年开始在患者中应用,因此我们现在积累了5年JAK抑制剂的使用经验。它们的作用逐渐明确,尤其在骨髓纤维化中。这类药物对患者原发病症状和脾大引起的症状的改善十分有效。还不知道的问题是它们在真性红细胞增多症或者血小板增多症患者慢性期中的作用。本次会议上有相关的发言,帮助我们更好的理解这个问题,也使我了解到现在很多实验正在进行。还有很多其他有趣的东西更侧重于实验方面,但是这些至少是我们转化研究的总结。
It is almost the ten-year anniversary of the initial publication that described the JAK2 mutation, which at the time exploded the myeloproliferative neoplasm field from a Cinderella specialty to an area where we could start to ask questions that were of fundamental importance, not just for patients with myeloproliferative neoplasm, but allowing us to make new advances that had really broad relevance. We now know that the JAK2 mutation is present in most patients with a myeloproliferative neoplasm.
We know there are additional exon 12 mutations present in a subgroup of patients who look like they have idiopathic erythrocytosis but in fact have a form of polycythemia vera. The JAK2 mutation has two major translational impacts. The first, and probably in some ways the most dramatic, is the impact it has had on diagnosis. It is now the front-line test used in Europe when a patient presents with high hemoglobin, for example. Instead of conducting a complex series of tests to make the diagnosis of polycythemia vera, all we need is a full blood count to show the hemoglobin is high and the molecular test to show the presence of a JAK2 mutation. Very simple.
And that has revolutionized diagnosis. Similarly, it has had a dramatic effect on essential thrombocythemia (ET). Of course in ET, roughly half of the patients lack the JAK2 mutation. So the most recent change there has been the discovery of the MPL mutation Gary Gilliland and Ross Levine and then more recently, the discovery of the CALR mutation by ourselves and Robert Kralovics’ group. Now we know the mutations that are responsible in around 80% of patients with ET as well. So making the diagnosis is a far more robust process now.
The second major impact is in the therapeutic area, of course. JAK2 inhibitors began use in patients in 2010 so we now have five years of experience of JAK2 inhibitors in patients. Their role is becoming clearer, particularly in myelofibrosis. They are very useful for patients who have constitutional symptoms and those who have symptoms attributable to splenomegaly. So they are very useful in that context. There are promising signs that they also may affect survival of these poor prognosis myelofibrosis patients. The unknown question is what their role will be in more chronic phase patients with polycythemia vera or essential thrombocythemia. There are presentations at this meeting that are starting to help us understand that and I know there are trials ongoing that are addressing that too. There is a lot of other exciting stuff we are doing on the more experimental side but that is the summary of our translational research.
《肿瘤瞭望》:您的团队首次证实了基因突变的顺序对临床上的血栓风险及治疗应答都有影响。临床上患者通常是出现了明显症状才去看医生的。您的这些研究结果对于临床有何意义?我们如何仅仅通过一次检查,就能够了解病人基因突变的顺序呢?
Green教授:这确实是一个挑战。我们的研究结果显示,如果疾病伴随两种突变(JAK2和TET2),疾病的生物学特点和临床表现并不相同,这取决于JAK2和TET2突变谁先发生。这对临床表现的影响颇有不同。例如,先发生JAK2突变的患者发病年龄较早,血栓发生率高。我们早期的数据显示这些患者对JAK2抑制剂靶向治疗反应也不相同。这个研究意义不仅在骨髓增殖性肿瘤中,首次证明适用于任何肿瘤中,获得性突变发生的顺序对肿瘤生物学特征及临床表现将会产生影响。
该原理的证明可能是最重要的发现之一,同时我希望这可以鼓励各个肿瘤领域的工作者不仅仅去关心发生了怎样的突变,也要去关注这些获得性突变的发生顺序。我认为这是一个非常重要的问题。你提出了我们如何简单地检测,这个比较实际的问题。目前来说这并不是很简单,因为标准的新一代测序技术很难准确确定两个突变发生的先后顺序。这主要是因为我们挑选了大量肿瘤细胞,并试图找出突变的等位基因。如何精确确定突变的先后顺序对现在的标准手段是一个挑战。然而,我认为现在一些新技术,如结合PCR和新一代测序可能会使突变顺序的检测变得更精确。如果这些被证明有效,我们将有信心可以在更大数量的患者中进行突变顺序检测,并且应用到所有肿瘤患者中。
That’s a challenge. The observation we made was if a disease is associated with two mutations (in our case JAK2 and TET2), the biology and the clinical behavior of the disease was different depending on whether JAK2 came first followed by TET2 or vice versa. The clinical impact of this was quite dramatic. The patient for whom the JAK2 mutation came first was at a much earlier age and had a higher rate of thrombosis, for example.
We had preliminary data suggesting that they may respond differently to targeted treatment with JAK2 inhibitors, for example. The importance of that is not just in the myeloproliferativeneoplasms, but first proof of principle that in any cancer, the order in which mutations are acquired makes a difference to the biology of the tumor and thus, its clinical behavior. The proof of that principle was probably one of the most important things and I hope that will stimulate people working in all types of cancer fields to ask questions not just about what mutations are present, but in what order were those mutations acquired.
I think that is a really fundamental issue. You raised the practical point of how do we measure this easily? That is not easy because standard next-generation sequencing technology finds it difficult to accurately determine what order two mutations have arrived in. This is mainly because we are taking a pool of tumor cells and trying to work out the allele burden. To do that with the precision necessary to determine order is challenging the standard techniques. However, I think there are some newer techniques that combine PCR and next-generation sequencing technology which may allow it to be more precise in how we measure mutation order. If this proves to be effective, then we will be in a very powerful position to determine mutation order in larger numbers of patients, not just the myeloproliferative neoplasms, but with a whole variety of tumors.