44 replies to this topic

[Trey]

There are 3 main types of Ph+ chromosomes, also called junction variants, called b2a2 (e13a2), b3a2 (e14a2), and e1a2.   A junction variant means that when the Ph+ chromosomes are formed, they are formed by chromosome 9 and chromosome 22 each breaking at a certain point along the chromosome and trading places.  These various designations show where the breakpoint occurs for each chromosome (the first part is the chromosome 22 breakpoint and the a2 portion is the chromosome 9 breakpoint)  Most people only have only one type of Ph+ chromosome, either b2a2 or b3a2, while e1a2 is less common.  I have both of the most common ones (b2a2 and b3a2), and it would seem that do you also.  You can read more about this in a previous posting:

http://community.lls.org/message/14536

The way you wrote this does not make much sense since e13a2 and e14a2 must be reported separately.  Would you write it out exactly as the report shows, and see also if e1a2 is mentioned.

[TeddyB]

Thanks Trey.

I wrote the results like they were presented, but might be i have a bad translation

It seems my results are presented as combined e13a2/e14a2, and as two separate results with both the ABL1 and GUS control gene.

No mention of the e1a2.

It seems that they call a pcr result of less than 0.1% for below or outside quantifiable area.

[Trey]

So it seems your PCR reports simply states a combined total of the e13a2 and e14a2.  It is not clear from that whether you actually have both breakpoints.  The total PCR must be a sum of all breakpoints if multiple ones exist.  You could ask your Onc if you have both breakpoints. 

It is more of an interesting anomaly than an issue.  The reason is that if CML starts with a single translocation in a high level blood stem cell, then why do some people have more than one type of Philadelphia Chromosome?  The answer is probably that a lower level stem cell may have a secondary breakpoint that results after the initial higher level translocation which starts the whole process. 

[TeddyB]

Yeah, either they are combined, or writing (e13a2/e14a2) on the front of the report is something they usually do, not sure. To be honest im hoping i dont have both, but seeing you and another guy (John) on this forum both reached pcru with both types, im really not that worried. Also with the response rates i have been having, im hopeful that i can maintain a long term response on 400mg Gleevec no matter if i have both types or not.

[TeddyB]

Mystery solved Trey.

Had my bloodwork done yesterday, and onc explained that it was like that on all reports, so i only have the one breakpoint.

Numbers were excellent (HBG 13.7, WBC 6.9(ANC 3.7), liver fine etc). Even my skin is its old self again (this took almost 8 months so i hope it lasts)

Now i just hope the next PCR is as good as, or better than the 6month result.

Anyway, this was the best xmas presant i could have hoped for

Now, if it only wasnt so damn cold, -20°C (-4°F)  is way to cold for me.