Hello. My name is Andrew Wei from Melbourne, Australia. And we’re here at the International Workshop for acute myeloid leukemia here in Nice in France. And today I’m joined by Dr Paresh Vyas from Oxford, and also Dr Jean Soulier from Hospital Saint-Louis in Paris. So today we had a pretty interesting session. Paresh, you talked about these new markers for secondary AML and Jean, you talked about some really interesting work from your lab. So, Paresh, do you want to just start by telling us about your session this morning?

Sure. Thank you.

So yes. Today we talked about the impact of molecular diagnostics, that is the assay for mutations in specific genes in acute myeloid leukemia. And what we’ve known for a very long time is that in acute myeloid leukemia, if you have a antecedent hematological illness such as myelodysplasia, patients generally do a little worse. What we have now begun to understand is that this clinical definition of secondary AML, as we call it, is probably not precise enough and that it’s much better measured by looking for specific genetic changes that are commonly seen in secondary disease but often are silent clinically. And in a large study of 1900 patients in Europe who were prospectively enrolled into clinical trials over the age of 60 intensively treated, i.e. treated with curative intent, clinically, 9% of those patients had secondary AML.

By contrast, if you look through genetic mutation analysis, 55% of these patients had the genetic mutational signature of secondary AML, and these patients do poorly and really do much better if they have an allo-transplant. And Paresh, many of these mutations are now contained within the ELN 2022 update of prognostic factors, but at the moment, only one of these markers is required to enter that category. You showed some interesting data where if you have multiple lesions, it’s worse. Do you want to comment on how you think this will be used in clinical practice?

Sure. So the new ELN 2022 guidelines really classify acute myeloid leukemia into different prognostic groups, i.e. groups that will do well versus those groups that do not do well. And the requirement for this classification is, as you mentioned, Andrew, that the presence of even just one of these mutations will put you into a more adverse group. What we’ve shown with this very large data set is that if you have more than one of these, and particularly depending on precisely which one you have and which cytogenetic abnormality you have, you get a much better separation of survival curves, meaning that we get a much more precise indication of how well these patients will do. How will this be used in clinical practice? Well, we would hope that when our data is peer reviewed and published, the community can look at this data, evaluate it independently for themselves. And we will be creating an app, which you can just have on your phone, and you can then use in the clinic in a very facile way.

Thank you. Jean Soulier, you presented some fascinating unpublished data today, which really gives us some fascinating insights into clonal hematopoiesis. Please tell us more about that.

Yes. So the title of my talk was germline acute myeloid leukemia. So it’s quite a vast field, and it appeared for the last years that besides the very classical

general predisposition, like Fanconi anemia, dyskeratosis congenita, more and more gene emerge. And so this this is a topic that concerns maybe 10% of the of the patients. And I’ve always been interested by those patients because of two reasons, it is quite rare in a cancer that you can predict that a significant proportion of the patients will develop leukemia. So it’s a very special situation in which you can have a look and see the different steps of progression to leukemia. And this is important for the patient, because then you can treat them, timely for the onset of the leukemia, just before the leukemia emerges as an overt leukemia. And then because we follow these patients every year with bone marrow aspirates to detect the first sign of the leukemia, you have all… and we keep the cells with their consent… We have a biobank for the 20 last years, a huge collection of samples – bone marrow samples – that makes all the way from, let’s say, normal to leukemia, and it allows us to study the first part of the disease, which is why patients have abnormal hematopoiesis and how this abnormal hematopoiesis makes the stage for several subsequent events to occur.

And then how it actually occurs at all stages, you know, so it gives a very dynamic view of the leukemia. So in my talk, I explained one of those diseases, the progression for one of the diseases – Fanconi anemia. And because historically, at the hospital, we received all the patients for France, and we have set up what we call a reference center. So all of them, they come to us and we diagnose and follow them. So this is we tried to do real translational research to connect, as actually did Dr Paresh Vyas for down syndrome, and I am convinced, I’m sure he’s convinced as well, that is good for those patients. And those patients are useful as well. And they are very willing to participate to learn many important insights for hematopoiesis, and in that particular case, it informs on those secondary leukemias in which the oncogenesis is not the same as de novo. Obviously, they are different.

For patients with adult onset Fanconi’s, are your findings relevant for adult physicians to think about and to screen? And how would they do that?

For diagnosis or for the follow-up?

For the implications of your research.

Yes, I think this is relevant because those patients they have a DNA damage repair syndrome.. a defect, and they are fragile.

And so nowadays, allogeneic bone marrow transplant is well tolerated. But still there is a toxicity, and unfortunately, those patients often have a shorter life than others. You know, they have an accelerated ageing. So I think it’s very important to to think a bit differently than we think for de novo leukemia, you know, de novo leukemia you want to cure. And you’re cured or not. Those patients you want to go with them as long as possible for the better life. So I think it’s important to treat them appropriately and timely, you know, not too toxic. And so this is why we have to learn a lot about what we can give them or not.

I was interested when you said that early on in the disease, p53 expression was very high. But then you didn’t find many p53 mutations later on, what was driving the increased expression of the p53?

Yeah, that’s really a great question. At the beginning, I was quite certain that because of those complex karyotype, we would find p53 mutation, which is the case in non…patient. You know, 75% of the patients with the complex karyotype have a p53 mutation. That wasn’t the case, so that was somewhat surprising.

And the thing is, those patients and their cells intrinsically, they are not hyper-mutating. And it was not in the field.. they have not many point mutations. What they have is chromosomal instability. So the way to rearrange the genome to make a somatic mutations is to make unbalanced translocation and small deletion and small gains. And this is what we see in the somatic cells from those patients, from the tumor cells of the patients. They accumulate short deletion and unbalanced translocation that leads to copy number abnormalities. And the most frequent of all and the one which goes along with the clonal hematopoiesis, is duplication of chromosome 1q.

So we did two things. The first is to understand why you have those 1q duplications so frequent. And actually I had no time to show that, but there is a fragile side, which is that the consensus point, which is broken very often in those patients. So I think that intrinsically they have a fragility there, so they have the facilities to duplicate chromosome 1q. And once they got this chromosome 1q, it confers to sell an advantage, and we know that because there is a correlation. But it’s not a demonstration, but we show it by in vitro and in vivo studies, that the duplication of chromosome 1q actually conferred an advantage to those cells. So in the minimal duplication… in the region which is minimally duplicated, there is one gene called MDM4 and MDM4 is an inhibitor of p53. So it makes sense.

And then our hypothesis was that three copies instead of two would confer a small overexpression… increased expression of 1.5 times, you know, very subtle expression. And to be really convinced of that, we made mice, transgenic mice. We didn’t take transgenic mice that were healthier that would lead to a massive overexpression.

We put the entire locus with the indigenous regulation sequence. So we put back the MDM4 gene just to really mimic what occurs in the patient, and these mice actually conferred an advantage to Fanconi anemia cells in the several models we could study.

And Paresh, last question. I was fascinated by your comment that in your study of secondary AML patients that only 9% were categorized. And yet the frequency of these secondary mutations was much higher than that. What do you think this is telling us about, I guess morphology, and the way we currently classify secondary AML?

Sure. So, as you’ve hinted, the bedrock of our diagnostics for a century or more has been morphology looking down a microscope. And if we see abnormal cells in a pre-leukemic environment, we call that dysplasia, and we think that there must be an antecedent hematological illness. I think what we also understand is that there is not a very good correlation between having a mutation and having dysplastic change, except for SF3B1 mutations and ring sideroblasts. So, for example, if you had a splicing factor mutation, SRSF2, or whatever, there’s no specific dysplastic change that says, Ah ha, you must have a secondary AML mutation. So I think what we’re now getting to is 2022. We’re getting to the age where, of course, morphology will still be important. But we’re getting to a situation where we’re beginning to think much more biologically, we’re thinking about are their genetic biomarkers that confer an advantage or disadvantage in terms of the treatment that’s applied or a patient receives. And those genetic biomarkers are really just a lot more accurate than the morphological biomarkers that we’ve been used to.

Well I think we’ve been treated to some fantastic data, all of which has been currently unpublished, which is giving us really important insights into the evolution of AML from a genetic perspective. Both from germline origins and also from antecedent MDS going into AML origins. And I just want to thank both of our discussants today, Paresh Vyas and Jean Soulier for their time. And thank you all for listening to this discussion.

Thank you.