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Concerned about my PCR results

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Hi there. On my last two PCR tests, I got the result: "BCR-ABL1 transcript detected near lower limit of assay" and 0.000% for both tests, which were three months apart. I've been on Gleevec for 15+ years and have been "undetectable" for most of it. Once in a while I get the "near lower limit-0.000%" result, but this is the first time I've received that result twice in a row. I am currently on 300mg per day and wonder if I should go back to 400mg because of these results. Any thoughts on what this kind of result means twice in a row? If you've had this result, how does your doctor interpret it?

I'm new here, so hello and nice to meet you all:)

They're super results. Right at the lower limit of the possible results. I'd be thinking of how much more could I reduce my dose, not whether an increase in required. 

David. 

Hi, David. Thanks for the optimistic reply. I do appreciate it. However, I'm so used to receiving "not detected" or "undetectable" results for 15+ years that this kind of repeated "detected" result spooks me.

For what it is worth I am 100% with David on this. My recent 0.005% compared to two previous 0.000% is within limits of test accuracy so need to worry. You are doing great. Did you see a reduction in side effects between 400mg and 300mg imatinib? If yes, I'd be tempted to try 200mg if you stay at the current level.

Welcome to this forum William.

To answer your question, I agree with both David and Alastair on this. The lab that does your PCR must have a pretty amazing method of detection. If  2 results show a near lower limit (of detection) = 0.000% BCR-ABL1, then you should be celebrating not worrying and considering this a rise. These kinds of numbers are very hard to quantify.

I had a reduced intensity stem cell transplant (RICSTC) in 2003 and waited until 2006 to receive PCR results that were (at that time) negative. Since that time my treatment centre has upgraded their PCR methodology/machine and their level of detection is pretty deep.... so surprise! my negatives turned to a low level detection of BCR-ABL1 - i.e 0.002%- sometimes 0.001%. My results have not show any further transcripts since the first results after the 'PCR machine' was upgraded. My doctor says it's not something to worry about...... the harder you look, the more likely you will find.

This very low level is hardly quantifiable - and I would add that PCR-U (undetectable) is a bit of a misnomer and entirely depends on which Lab, using which methodology/assay/control gene/the level of normal (control) transcripts in the particular samples tested -i.e normal ABL1 or BCR or GUSB (depending on which of these your lab uses as a control) genes where present. 

There are many variables with PCR testing but as long as you do not see levels rise enough for you to lose a 'log' or a zero - repeated at least twice, then you are doing really, really well. 

Sandy

Hi Sandy,

I think it is important for our community to know and to understand where the number "9" and number "22" chromosome sit in our hematopoietic stem cells.

They are right next to each other. And also - the points that are in "contact" - wouldn't you know it - are right at the bcr and abl junction points.

Now is it any surprise that during cell replication, the abl part of number 9 chromosome will just so happen to 'translocate' with the bcr part of number 22 chromosome since they sit right next to each other?

Is it any wonder that not every human on this planet has CML! The reality is that translocation of number 9 and number 22 chromosomes creating the bcr-abl oncogene is probably very very common. In fact, it's probably natural. But - through natural selection (yes, I do believe in evolution) - bcr-abl was selected out for destruction. It doesn't work. BCR-ABL causes tyrosine kinase to go unchecked in WBC growth. T-cells kill it  - and on a regular basis - because bcr-abl happens all of the time.

To your point that the 'harder you look' - there they are! Everyone has bcr-abl (I would place a huge bet on that one). It's just that bcr-abl is kept in check for most people. We - who get CML - lost the ability to destroy, defend - prevent bcr-abl. TKI's have given us a second chance. 40-50% of us who reach PCRU - no longer need TKI's. Treatment free remission they call it. I call it - "functional cure".

Any of us worrying about 0.00X % bcr-abl are worrying themselves sick for no reason. TKI's have given us a new lease on life. And maybe - just maybe - a chance for our own immune system to get back in the game. No one - ever - need die of CML again.

 

 

 

I'm deeply grateful for the replies here. Thank you to all of you!

 

Hi Scuba, yes.... See our booklet on q-PCR for a background on chromosomes, what they are, where they are and a nice visual of the 9/22 translocation.

Page 4 onwards.   https://www.cmlsupport.org.uk/sites/default/files/qrt-pcr-primer.pdf

Sandy