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Understanding Your CLL Diagnosis: What Tests Are Recommended to Figure Out Your Genetic Subtype?

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Published on April 22, 2019

How is a person’s chronic lymphocytic leukemia (CLL) genetic subtype identified after diagnosis? Noted CLL expert Dr. Philip Thompson, from The University of Texas MD Anderson Cancer Center, explains what chromosomal abnormalities to look for in CLL patients, what tests are recommended and how mutational status impacts the course of care. Tune in to learn more about genetic testing, prognostic indicators and monitoring CLL over time.

Provided by CLL Global Research Foundation, which received support from AbbVie Inc., Gilead Sciences and TG Therapeutics.



CLL Global Research Foundation

Transcript | Understanding Your CLL Diagnosis: What Tests Are Recommended to Figure Out Your Genetic Subtype?

And the importance of looking for those is twofold.  Firstly, it gives us an idea of how quickly is the disease likely to grow because some of the chromosomal abnormalities that we find on FISH, for example a deletion on chromosome 13q, are generally associated with a slower growing disease, whereas some of them like a deletion on chromosome 11q or 17p are generally associated with a more rapidly growing disease.  Now, not always but in general.  And then those things can also give you an idea of what the best treatment might be later on. 

The second thing we look at is what we call the immunoglobulin heavy chain variable mutation status, and we usually just shorten that to mutation status.  It gets a bit confusing for patients because this is a situation where it's good to be mutated, which is counterintuitive.  Basically what it means is that the CLL comes from a B lymphocyte, which is part of your immune system.  And a B lymphocyte's job is to go around in lymph nodes and circulate around in the blood until it finds an infection. 

When it finds infection it has a probe on the surface called immunoglobulin, which is the same thing as an antibody, and that recognizes a microbe like a bacteria.  And then when it does that it tries to make the best possible antibody, and in order to do that it actually mutates the antibody gene or the immunoglobulin gene.  And when you have a CLL that arises from a B lymphocyte that has a mutated immunoglobulin gene it's a more mature B lymphocyte.  It's been around for a while, and it has less growth potential than an unmutated CLL.  So we look at that, and actually that's a very good indicator for us as to how likely a patient's disease is going to grow more or less quickly over time. 

Now, do you have to do that when the patient's first diagnosed?  I would say no, you don't, because we're always going to follow patients anyway by seeing them generally after diagnosis I would see a patient approximately every three months, and we're going to keep checking their blood tests and we're going to keep examining their lymph nodes and their liver and spleen, so we'll be able to tell if they're growing quickly or not, and that's actually best test.  But a lot of the time patients when they come to see you initially they want to know the most information that they possibly can, and that's the reason we like to do those tests. 

The other thing I would say is that the mutation status of the cells doesn't change over time, so if you do it once you don't have to keep repeating it down the line.  It will be the same for the whole course of a patient's disease.  So those are the two biggest ones we do. 

You can look for mutations in individual genes within the CLL cells.  That has more relevance, to be honest, in terms of deciding treatment rather than deciding how quickly it's going to grow at the start, and in many cases it's not done outside of a few research centers. 

Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

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