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What Should You Know About CLL Genetic Testing?

What Should You Know About CLL Genetic Testing? from Patient Empowerment Network on Vimeo.

In chronic lymphocytic leukemia (CLL) diagnosis and disease management, genetic testing plays a key role. Dr. Jennifer Woyach explains what is examined in CLL genetic testing, the timing and administration of testing, and testing advances.

Dr. Jennifer Woyach is a hematologist-oncologist specializing in chronic lymphocytic leukemia (CLL) at Ohio State’s Comprehensive Cancer Center – James Cancer Hospital & Solove Research Institute. Find out more about this expert here. 

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Could CLL Be Inherited?

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Transcript:

Katherine:                  

Before we get deeper into our conversation about genetics, there are a few terms that patients are often confused by. As a primer, I thought we could start by defining some of these terms. First, what is genetic or molecular testing?

Dr. Woyach:               

So, all cancer cells will have a collection of mutations or abnormalities in the DNA that either make the cell a cancer cell or make it behave in a certain way. And so, these mutations are referred to as the genetic abnormalities of the CLL cells. So, when we talk about genetic testing in CLL, we use it to mean a number of things. We can use it to look specifically for types of mutations so types of genetic abnormalities.

 We also sometimes use that as a kind of catch-all term like genetic or molecular testing also to refer to looking at changes in the chromosomes inside of a CLL cell. That’s also called cytogenetic testing. And then, we also use a number of tests in CLL where we look at specific, not necessarily abnormalities, but just changes in the cell that can indicate a certain type of behavior.

Katherine:                

How is this different from genomic testing?

Dr. Woyach:               

So, genetic and genomic testing, I think, are usually used interchangeably. But sometimes, we use them in different contexts but they really mean the same thing in this case.

Katherine:                  

Okay. And what is a chromosome change?

Dr. Woyach:              

So, as you might remember from biology class maybe a long time ago, as it was for me, inside a cell, so a normal cell or a cancer cell, you have the nucleus, which holds the DNA.

And the DNA is organized into chromosomes. And so, when a cell goes through division, it takes those chromosomes, copies them and then, breaks them apart into two different cells. So, changes can happen in the level of the DNA itself. So, a mutation where one base is changed to something different. So, that would be just like a single nucleotide change. And that’s something you’re not going to see as a change to a chromosome. Another thing that can happen in CLL and in other cancers, too, is that during that process of cell division, an entire chromosome could be duplicated. It could be absent.

More commonly, parts of chromosomes can change. This is all because cancer cells just do a very poor job of editing their division.

An in normal cells, there are multiple steps along the way from the process of copying the genes to copying the chromosomes to doing the division. And every step along the way, if something happens incorrectly, which happens a lot, the cell usually just dies. But a cancer cell is not going to do that because it has so many signals that keep telling it to stay alive that it can tolerate a lot of different abnormalities. And so, you end up with cells that are just very different from what you would see normally.

Katherine:                  

All right. Well, that’s a great way for us to start. Let’s go into the discussion of the relationship between testing and CLL. How is testing administered?

Dr. Woyach:               

So, almost all testing, in terms of molecular genomic testing in CLL, can be done on a blood sample. So, that’s one important thing.

The CLL guidelines recommend that testing for certain prognostic factors be done before the administration of therapy. So, at the very least, before somebody starts treatment, they should have these tests performed. In my practice and I think most CLL specialists find it really helpful to do these tests, not necessarily just at the time of treatment but really at the time of diagnosis or the time we first see the patient because CLL is a very heterogenous disease, which means that it behaves very differently in different people. So, there are some people that are diagnosed and will go 10 or 20 years before they need any treatment.

And many don’t need treatment at all. Whereas other people are very likely to need treatment within the first few years after diagnosis. Some of the genetic tests that we do can help counsel patients on where they’re likely to fall in that spectrum.

And so, I think that’s helpful for people to know early on in the disease course. But really, the tests can be performed at any time before treatment

Katherine:              

Have there been advances in testing?

Dr. Woyach:               

Absolutely. I think in every cancer, we’ve learned so much more about the biology of the disease, specific mutations that cause specific behaviors of cells, and really much more in CLL about the common genetic changes and what those means to response to therapy.

What Is CLL and How Is It Diagnosed?

What Is CLL and How Is It Diagnosed? from Patient Empowerment Network on Vimeo.

What exactly is chronic lymphocytic leukemia (CLL), and what factors help determine a diagnosis? Dr. Jennifer Woyach explains how CLL originates and transforms, the tests involved in diagnosis, and shares a common misconception about CLL.

Dr. Jennifer Woyach is a hematologist-oncologist specializing in chronic lymphocytic leukemia (CLL) at Ohio State’s Comprehensive Cancer Center – James Cancer Hospital & Solove Research Institute. Find out more about this expert here. 

See More From INSIST! CLL


Related Resources

 

What Should You Know About CLL Genetic Testing?

What Tests Should CLL Patients Insist They Receive?

What Does It Mean to Have High-Risk CLL?

 

Transcript:

Katherine:                  

Well, Dr. Woyach, let’s start by understanding CLL. Would you briefly walk us through what CLL actually is?

Dr. Woyach:               

Sure. CLL is a cancer of the blood, the lymph nodes, and the bone marrow.

And it happens when a particular type of white blood cell called a B lymphocyte acquires genetic mutations and transforms into a cancer cell. And then, over time, those cancer cells continue to grow and divide. And they can cause symptoms such as enlarged lymph nodes if the cells get stuck in the lymph nodes and continue to grow there. It can cause a high white blood cell count, which usually doesn’t cause any symptoms but is one of the things that we see often in CLL. And then, it can also cause the bone marrow to not be able to produce normal cells because it can get so infiltrated or so full of CLL cells.

And this can cause things like anemia, which is lowering of the red blood cell count and thrombocytopenia, which is lowering of your platelet count.

Katherine:                  

What are the steps involved in reaching a diagnosis?

Dr. Woyach:               

CLL is an interesting disease because it’s one of the only cancers that does not require a biopsy of something for a diagnosis.

So, we can, actually, make the diagnosis of CLL based on the peripheral blood. So, just a blood draw in somebody’s doctor’s office. Usually, CLL is diagnosed in the asymptomatic stage. So, somebody goes to their primary care doctor, has blood drawn usually for another reason, and is found to have a high white blood cell count or sometimes even a fairly normal white blood cell count but a high percentage of lymphocytes. That certain type of cancerous white blood cell. So, the next step in the diagnosis then is something called peripheral blood flow cytometry, which is a specialized test where we look at the markers or antigens on the surface of white blood cells.

So, there is kind of a code of these markers on the surface of all of your blood cells that can tell what type of cells they are. So, for CLL in particular, we’ll see that the cells express some of the normal markers we would see on a normal B lymphocyte.

Things like CD19, CD20, CD23. But they also express a marker called CD5, which is found on normal T lymphocytes but shouldn’t be found on B lymphocytes.

And so, this collection of surface markers can make the diagnosis of CLL. Sometimes, we do need to do extra studies like a bone marrow biopsy or a lymph node biopsy. But often times, those are not necessary at the time of diagnosis.

Katherine:                  

When you meet with patients, Dr. Woyach, what are some common misconceptions that you hear about?

Dr. Woyach:               

I think the biggest thing that I hear, and granted I see a lot of patients after they’ve been diagnosed by someone, gone to see an oncologist and then, come to me after, but one of the common things that I hear is that somebody has told them along the way that they have the good type of cancer, which I think is not a very helpful thing to hear as a patient because, of course, no cancer is a good type of cancer.

I think it’s important to note that CLL is one that has a lot of treatment options and usually extended survival. But I think that’s one of the most common misconceptions that I hear.