[blair77]

Non-clonal chromosome loss?

by blair77 on Sat Jan 03, 2015 11:54 pm

Does anyone know what a non-clonal chromosome loss on a bone marrow biopsy (BMB) means? The BMB report also says NO evidence of common multiple myeloma associated abnormalities (then goes on to list all the things that were NOT found). So why the chromosome loss and does it have any implications?

[Dr. Ken Shain]

Re: Non-clonal chromosome loss?

by Dr. Ken Shain on Mon Jan 05, 2015 12:53 am

It is difficult to answer your question without knowing what was actually assayed and what chromosomes were not at the appropriate numbers. Further, we need to know what test, or tests, were run. Metaphase cytogenetics and/or FISH are generally the most common, with FISH (specifically multiple myeloma FISH) being the most appropriate today. We also do not know what the FISH results were at diagnosis (unless this is a diagnosis marrow).

In multiple myeloma, we know that certain chromosome gains, losses, deletions, and translocations are associated with the disease. Additionally, these can be harbingers of favorable or unfavorable (high) risk disease. Gains in 1q21, losses in 1p31, t(4;14), t(6;14), t(11;14), del(13)q, t(14;16), t(14;20), del(17)p, hyperdiploidy of odd numbered chromosomes, and hypodiploidy (loss of chromosomes) are common chromosomal abnormalities in myeloma.

With age, however, some chromosomes can be lost generally speaking, such as the Y chromosome in men, without specific implications.

Again, with a lack of context, the absence of a myeloma-associated genetic anomaly can stem from the fact that there are no anomalies in the myeloma cells at the time of the bone marrow biopsy, not all the tests were run, or there were no multiple myeloma cells to assay (which would be a good thing).

I am not sure if I was able to satisfactorily answer your question. Maybe with more clarity either I or one of our other Beacon Medical Advisors can shed more light on the subject.