We are brainstorming about research involving the fields of genetics and oncology. We were wondering if chemotherapy could interfere with the results of the DNA isolation and Genetic results. Would it be possible to get blood samples during chemotherapy or is it best to do this between chemotherapy sessions?
Thanks in advance,
Roel
No, there is no sign of influencing, at least with the routine examinations.
In my experience, when patients are receiving chemotherapy, there is no problem at all in extracting DNA, however it is sometimes difficult to amplify that by PCR . So I prefere to extract DNA before or a couple of months after chemotherapy, if that is possible of course
Well,in my experience i never had problems in DNA extraction and amplification
Chemotherapy causes short-term falls in the numbers of circulating white blood cells, particularly neutrophils in mid cycle (typically second week). If white blood cell counts are very low then obtaining DNA from blood samples may be difficult. In general however the wide-spread use of colony stimulating factors (G-CSF) to protect patients from the risks from myelo-suppressive chemotherapy treatment means that very low counts are uncommon so this is unlikely to be a problem in practice.
Although chemotherapy drugs damage DNA, this is unlikely to affect testing for specific DNA mutations. Furthermore white blood cells with chemotherapy-induced DNA damage don't survive. The fall in counts results during chemotherapy is caused by damage resulting in apoptosis to progenitors. Therefore this is not a problem in practise.
Overall although genetic testing during chemotherapy is not ideal, it can be done.
I do not think or ever read that chemotherapeutic drugs (they damage DNA either directly such as alkylating agents and platinum compounds or indirectly by interfering with the cell cycle; antimetabolites or anti-mitotic drugs, leading to apoptosis) influence the results of DNA testing either in peripheral blood/buccal mucosa samples (seeking for germ-line gene alterations), or tumor tissue (when looking at specific tumor-related genetic alterations).
Chemotherapy does not change genetic structure of the individual.Whilst DNA damage /RNA damage induced at cellular level is the mechanism of cell death
he individuals genotype does not change.DNA defects may be brought to the fore,second cancers induced but the genetic make up of the treated patient will remain the same,so testing even whilst on treatment should remain the same(A BRCA abnormality at germline will remain).Genetic testing of the tumour is different as with different treatments different clones of tumour cells may be differentially affected ,resulting in selection of a more resistant clone.
h
I think the answer depends on what you intent to measure and what the details are. Chemotherapy can induce somatic DNA alterations and potentially predispose to acquired aberrant clonal expansions (https://www.nature.com/articles/gim2017196). Are you plannig to get blood samples for germline DNA testing? Hematologic malignancy testing? Cell free DNA?
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