If someone can straighten out my confusion, I am a little unsure how to interpret percentages in a few different cases.
1. When one talks about 40% plasma cells in a bone marrow aspiration at diagnosis, does this mean 40% of all the cells in the sample are plasma cells (both ordinary and abnormal) or does this mean 40% of all the cells in the sample are abnormal plasma cells meaning myeloma cells?
2. If one does the fish test and talks about 48% of the cells being deletion 17p, does this mean that
(a) 48% of all the cells in the sample are myeloma cells having the deletion 17p or does it mean that
(b) 48% of all the plasma cells in the sample are myeloma cells having the deletion 17p, or does it mean that
(c) 48% of all the myeloma cells in the sample have the deletion 17p?
Thanks for any help.
Ping.
Forums
Re: Test percentage Interpretation
Ping,
You should verify this with your doctor, but my understanding has always been that a bone marrow plasma percentage (BMPC) is the total percentage of plasma cells in an overall cell population, regardless of whether those plasma cells are malignant or not.
Also, I believe that when one runs a biopsy sample through a FISH test, the FISH test does not distinguish between normal and malignant plasma cells when looking for a specific mutation. Therefore the percentage of del 17p cells being reported is the percentage of ALL plasma cells (normal or otherwise) that are exhibiting the del17p mutation.
Having said that, if you have a 40% BMPC reading, then the vast majority of your bone marrow plasma cells are malignant, assuming that a normal BMPC percentage reading is 5% or less.
But again, you should verify this with your doctor. If somebody else has a different understanding, please chime in.
You should verify this with your doctor, but my understanding has always been that a bone marrow plasma percentage (BMPC) is the total percentage of plasma cells in an overall cell population, regardless of whether those plasma cells are malignant or not.
Also, I believe that when one runs a biopsy sample through a FISH test, the FISH test does not distinguish between normal and malignant plasma cells when looking for a specific mutation. Therefore the percentage of del 17p cells being reported is the percentage of ALL plasma cells (normal or otherwise) that are exhibiting the del17p mutation.
Having said that, if you have a 40% BMPC reading, then the vast majority of your bone marrow plasma cells are malignant, assuming that a normal BMPC percentage reading is 5% or less.
But again, you should verify this with your doctor. If somebody else has a different understanding, please chime in.
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Multibilly - Name: Multibilly
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Smoldering, Nov, 2012
Re: Plasma cell & chromosomal abnormality percentages
Just to add a bit to Multibilly's very helpful response, I believe it sometimes is the case that a bone marrow biopsy report will note the "clonal plasma cell percentage", which would be the percent of all marrow cells that are clonal (myeloma) plasma cells.
The clonal percentage is actually the plasma cell percentage that is supposed to be used when diagnosing MGUS, smoldering multiple myeloma, and symptomatic multiple myeloma patients, according to the revised IMWG diagnostic criteria published a couple of years ago.
The difference between the "clonal plasma cell percentage" and "plasma cell percentage" should generally be just a few percentage points.
The clonal percentage is actually the plasma cell percentage that is supposed to be used when diagnosing MGUS, smoldering multiple myeloma, and symptomatic multiple myeloma patients, according to the revised IMWG diagnostic criteria published a couple of years ago.
The difference between the "clonal plasma cell percentage" and "plasma cell percentage" should generally be just a few percentage points.
Re: Plasma cell & chromosomal abnormality percentages
Cheryl,
Good to hear from you! As usual, you keep me honest. I just found this earlier thread on the matter that supports your interpretation.
https://myelomabeacon.org/forum/what-is-the-correct-plasma-cell-percentage-to-use-t5894.html
In any case, it will be important to look at the exact language in a pathology report to clearly understand just what is being reported.
Good to hear from you! As usual, you keep me honest. I just found this earlier thread on the matter that supports your interpretation.
https://myelomabeacon.org/forum/what-is-the-correct-plasma-cell-percentage-to-use-t5894.html
In any case, it will be important to look at the exact language in a pathology report to clearly understand just what is being reported.
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Multibilly - Name: Multibilly
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Smoldering, Nov, 2012
Re: Plasma cell & chromosomal abnormality percentages
Not to change the subject, but do all myeloma cells have abnormal chromosomes?
I think I was wrong when I thought I had abnormal chromosomes (possibly in every cell of my body) which 'lead' to myeloma cells. I now don't know if it is the egg or chicken which comes first between myeloma cells and chromosomal abnormalities.
If you are MRD negative (by all test methods), wouldn't your chromosomes test normal? Or at least have non-clonal abnormalities
I think I was wrong when I thought I had abnormal chromosomes (possibly in every cell of my body) which 'lead' to myeloma cells. I now don't know if it is the egg or chicken which comes first between myeloma cells and chromosomal abnormalities.
If you are MRD negative (by all test methods), wouldn't your chromosomes test normal? Or at least have non-clonal abnormalities
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blueblood - Name: Craig
- Who do you know with myeloma?: Myself
- When were you/they diagnosed?: March 2014
- Age at diagnosis: 54
Re: Plasma cell & chromosomal abnormality percentages
Craig - The chromosomal abnormalities are in your myeloma cells, not the cells in the rest of your body. If you are are MRD negative, it will be hard or nearly impossible to test for chromosomal abnormalities because you have to have myeloma cells for that testing. That's why people who have a "dry tap" bone marrow biopsy at diagnosis don't have information about whether they are high-risk or standard risk:
Almost by definition, myeloma cells have to have some sort of genetic mutation to misbehave the way they do (compared to normal plasma cells) However, standard FISH testing won't necessarily pick up such mutations. So there are myeloma patients who do not have any chromosomal abnormalities as determined by standard testing.
Multibilly - Just trying to help a little bit. You do such a great job most of the time, it isn't very often that I need to add to what you've posted.
Almost by definition, myeloma cells have to have some sort of genetic mutation to misbehave the way they do (compared to normal plasma cells) However, standard FISH testing won't necessarily pick up such mutations. So there are myeloma patients who do not have any chromosomal abnormalities as determined by standard testing.
Multibilly - Just trying to help a little bit. You do such a great job most of the time, it isn't very often that I need to add to what you've posted.
Re: Plasma cell & chromosomal abnormality percentages
Cheryl,
Thanks.
I never understood the term 'dry tap' either. I assumed the pull didn't draw 'any' cells, and never understood why they didn't reload another syringe. A 'dry tap' doesn't capture any myeloma cells to analyze.
Thanks.
I never understood the term 'dry tap' either. I assumed the pull didn't draw 'any' cells, and never understood why they didn't reload another syringe. A 'dry tap' doesn't capture any myeloma cells to analyze.
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blueblood - Name: Craig
- Who do you know with myeloma?: Myself
- When were you/they diagnosed?: March 2014
- Age at diagnosis: 54
Re: Plasma cell & chromosomal abnormality percentages
Craig,
I tend to agree with you regarding your statement: "I assumed the pull didn't draw 'any' cells, and never understood why they didn't reload another syringe".
When I had I had my one and only bone marrow biopsy, the sample was sent up to the lab for a quick evaluation while I was lying on the table. I was then informed that they had "a good sample", and we moved on. I assumed if it were otherwise that I would have had another sample drawn?
I tend to agree with you regarding your statement: "I assumed the pull didn't draw 'any' cells, and never understood why they didn't reload another syringe".
When I had I had my one and only bone marrow biopsy, the sample was sent up to the lab for a quick evaluation while I was lying on the table. I was then informed that they had "a good sample", and we moved on. I assumed if it were otherwise that I would have had another sample drawn?
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Multibilly - Name: Multibilly
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Smoldering, Nov, 2012
Re: Plasma cell & chromosomal abnormality percentages
Good morning:
I am quite sure that I do not have as complete grasp of this issue as I would like to. So, if a couple of our very knowledgeable posters (Cheryl and Multibilly, et. al.) would tell me if this sounds right, I would be appreciative.
1. A bone marrow biopsy takes a sample of the aspirate (bloody stuff) and the actual marrow. One of my issues is that I am not clear as to exactly what test is done to which part of the sample.
2. They look at the marrow and call out the % of plasma cells. This is done (I think) on the marrow. Typically, it looks like they will make a call to within 5%. A normal, healthy person, could have about 4% of the cells. The myeloma cells look like plasma cells under the microscope. If you are more than 5%, then there is an issue. If you are less than 5%, then as far as the visual inspection is concerned, you are non-detect, and may be OK, but also there may be a low level of multiple myeloma.
3. More advanced flow cytometry is done on the aspirate. This looks at "markers" on the surface of the cells in the aspirate, and can actually call out the bad multiple myeloma cells (distinguishing between good and bad plasma cells). This can determine the presence of multiple myeloma cells down to about 1 in 100,000 or one in a million. This would the be MRD negativity test.
4. Before the wide availability of flow cytometry, they would define CR as no M-Spike (and no light chains) and less than 5% plasma cells. With flow cytometry, you can pick up the case of the presence of multiple myeloma cells, at a visual level of less than 5% plasma cells.
Does this sound correct? Or am I mistaken in any respect. Thanks in advance.
I am quite sure that I do not have as complete grasp of this issue as I would like to. So, if a couple of our very knowledgeable posters (Cheryl and Multibilly, et. al.) would tell me if this sounds right, I would be appreciative.
1. A bone marrow biopsy takes a sample of the aspirate (bloody stuff) and the actual marrow. One of my issues is that I am not clear as to exactly what test is done to which part of the sample.
2. They look at the marrow and call out the % of plasma cells. This is done (I think) on the marrow. Typically, it looks like they will make a call to within 5%. A normal, healthy person, could have about 4% of the cells. The myeloma cells look like plasma cells under the microscope. If you are more than 5%, then there is an issue. If you are less than 5%, then as far as the visual inspection is concerned, you are non-detect, and may be OK, but also there may be a low level of multiple myeloma.
3. More advanced flow cytometry is done on the aspirate. This looks at "markers" on the surface of the cells in the aspirate, and can actually call out the bad multiple myeloma cells (distinguishing between good and bad plasma cells). This can determine the presence of multiple myeloma cells down to about 1 in 100,000 or one in a million. This would the be MRD negativity test.
4. Before the wide availability of flow cytometry, they would define CR as no M-Spike (and no light chains) and less than 5% plasma cells. With flow cytometry, you can pick up the case of the presence of multiple myeloma cells, at a visual level of less than 5% plasma cells.
Does this sound correct? Or am I mistaken in any respect. Thanks in advance.
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JPC - Name: JPC
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Multibilly - Name: Multibilly
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Smoldering, Nov, 2012
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