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What does a FISH BCR-ABL1 t(9,22) percentage tell me?

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My latest FISH percentages have been steadily I creating for the past year. In November, 2022, it was 55% and, after a second BMB last week, it is 65%. My molecular genetics values have been "Undetected," log>5. I'm really confused because my doctor is prescribing 100mg Sprycel. I've been taking 300mg Gleevec since December, 2020, when I was first diagnosed.
Thank you all for your thoughts.

If you're not already, I think it would be wise for you to consult a CML specialist. It's atypical for your FISH results to be so different from the PCR reports.

Has your doctor ordered a BCR-ABL1 mutation test?

I don’t understand why you are having bmb biopsies when you’re >5 log reduction with molecular monitoring for one.

No, not that I have been briefed. I'm definitely not comfortable with how my case is being handled. I have contacted M.D. Anderson about obtaining a second opinion and, perhaps, additional testing.
Thanks for your reply.

I'm not sure either. It could be that I showed concerned about the high FISH and the sustained log>5 reduction.

Is this possibly some sort of atypical CML?

Generally FISH from bone marrow results correlate well to PCR (molecular) results from blood. Clearly they are not correlating in your case.

At the heart of it, CML is a disease of the bone marrow not of the blood - despite it labelled as “blood cancer”.

A second opinion is wise, but your current doctor may not be far off the mark if your marrow is continuing to test (highly) positive.

David.

It is not possible for you to have a FISH percentage (>50%) and be undetected for bcr-abl at the same time unless FISH was used for a different blood disorder (not CML). There could be an error somewhere either by your doctor or in what you are reporting. Is it possible for you to post your FISH report as written?

To be clear, PCR for CML is a very specific molecular test to detect bcr-abl protein. FISH is a visual 'under the microscope' view of florescence tied to specific DNA (in CML --> bcr-abl) strands. FISH can be used in a number of DNA tests. You need to be sure (you and your doctor) that the FISH test reported is specific to CML. I suspect it is not.

It is entirely possible you have positive FISH for a different blood disorder such as CLL which could explain FISH at >50% and bcr-abl undetected. Sprycel is used to treat CLL. Ask your doctor and be sure of what you have and what the tests mean. ASK questions. Getting a second opinion is very wise regardless.