3 replies to this topic

[August1]

Hi everyone,

Just had a quick question: What tests are used to check for additional Chromosome Mutations other than the typical BCR-ABL t(9:22)? By this I mean actual additional chromosomal anomalies (ACA) and not Kinase Mutations.

On my last BCR-ABL1 Gene Rearrangement Quantitative PCR test it stated the following.

P190 BCR-ABL1 Not Tested

P210 BCR-ABL1 detected

I think in my case this means I have the "classic" P210 translocation (and they didn't bother to test for P190). I was curious if they check for additional chromosomal anomalies as well or if a more specialized test is needed?

Thanks,

Bill

[ChrisC]

Hi Bill,

Good question. I have no idea or knowledge about other tests, and/or what they might mean, sorry. It will be interesting to learn more if/when some knowledgeable folks post their replies.

Just for the record, since I got my test results yesterday (no idea what it means):

P190 BCR-ABL1  Not Detected

P210 BCR-ABL1  Not Detected

If these are important markers for treatment, it would be good to know more.

Good luck with regaining a strong downward PCR score. At one point early on, I was off Gleevec for four weeks and my PCR and WBC increased in my next testing. After restarting Gleevec for one week I switched to Sprycel, on which I became permanently PCRU within four months.

Testing for being on the right TKI for one's individual treatment: this would be a helpful test!

ChrisC

[Rissa]

According to my lab results, P190 refers to the e1a2 transcript, and P210 refers to the b2a2 and b3a2 transcripts.  I think the "P" stands for protein. 

[Trey]

Bill,

What you said is correct.  You have the typical P210 (either b2a2 or b3a2) Philadelphia Chromosome.  You could also have the P190 but you say your Onc has not tested for it.  As a side issue, testing for P190 (e1a2) using the PCR test is optional on the PCR order form, and most patients probably do not realize this.  I do not agree with never testing for  P190 (e1a3).  After an initial test for P190 at diagnosis, deleting P190 from later PCR tests should be fine unless there is a rapid rise in PCR.  FISH will detect all these variants. 

Now for your real question.  Other chromosome mutations/anomalies would be reported primarily on the Bone Marrow Biopsy (BMB) report, and maybe also on a FISH or PCR report.  Overall the BMB is the best source for such issues.  If your BMB report says t(9;22)(q34;q11) and the BMB text does not list anything additional then you do NOT have additional mutations.  Additional mutations would usually be inserted into the t(9;22) string.  An example would be the following:  t(1;9;22)(q32;q34;Q11) which shows that in addition to a translocation between chromosomes 9 and 22 there is a 3-way mutation involving chromosome 1.  Another example t(8;9;22) (q21;q34;q11.2) shows chromosome 8 is involved.  There can be derivative chromosomes shown by "der" in the string as in example: der(9)t(9;22)(q34;q11) showing loss of genetic material from chromosome 9 before attaching to 22.  This would be more of an anomaly to the primary mutation rather than an additional mutation  You might also see a +8 or -7 inserted in the string, meaning an extra chromosome 8 (trisomy 8) or missing a chromosome 7 (monosomy 7).

http://www.molecular.../content/3/1/15

Ask your Onc directly whether you have any additional chromosome mutations or anomalies.