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Updated: Aug 8, 2026
An Automated Method to Perform The In Vitro Micronucleus Assay using Multispectral Imaging Flow Cytometry
Published on: May 13, 2019
Micronucleus analysis in peripheral blood lymphocytes from melanoma patients treated with dacarbazine
Background:
Dacarbazine is an antitumor drug used with considerable success in the chemotherapy of a number of human neoplasias, particularly advanced disseminated melanoma. Dacarbazine is mutagenic in prokaryotic and eukaryotic cells, but no effect in vivo have been evaluated.
Materials And Methods:
Peripheral blood lymphocytes from patients with metastatic melanoma undergoing dacarbazine chemotherapy every 21 days for a total of 7 cycles, were analyzed for the presence of micronuclei with the CREST antikinetochore antibody technique. Cytogenetic analysis on blood samples collected just before and 2 hours after the therapy was carried out at 48, 72 and 96 hours following lymphocyte stimulation.
Results:
A significant increase in micronucleus frequency was found at both 72 and 96 hours after therapy. For the only two patients analyzed after more than one cycle, a decrease in micronuclei was observed after the third and the fourth therapy. Moreover, the CREST antibody technique showed that the frequency of micronuclei containing whole chromosomes (CREST+) was significantly higher after therapy at 72 and 96 hours. As the frequency of micronuclei containing acentric chromosome fragments (CREST-) was not significantly increased after therapy, either at 72 or 96 hours after lymphocyte stimulation, we suppose that DTIC mainly acted as an aneugenic agent.
Conclusions:
The lack of a significant micronucleus increase at 48 hours could suggest that this culture time is too short for providing cultures with a sufficient large number of diving cells. In conclusion, our results have shown that dacarbazine induced chromosome loss in lymphocytes from patients treated with this drug.
Insights
Dacarbazine chemotherapy increases micronuclei in melanoma patients, indicating it causes chromosome loss in vivo. Further cycles may reduce this effect, suggesting a complex aneugenic mechanism.
Area of Science:
- Oncology
- Cytogenetics
- Pharmacology
Background:
- Dacarbazine is a successful antitumor drug for advanced melanoma.
- Dacarbazine is known to be mutagenic in cell cultures.
- In vivo mutagenicity of Dacarbazine has not been evaluated.
Purpose of the Study:
- To evaluate the in vivo genotoxic effects of Dacarbazine in melanoma patients.
- To assess Dacarbazine's impact on micronucleus formation in lymphocytes.
Main Methods:
- Peripheral blood lymphocytes from metastatic melanoma patients undergoing Dacarbazine chemotherapy were analyzed.
- Micronuclei detection using the CREST antikinetochore antibody technique.
- Cytogenetic analysis performed at 48, 72, and 96 hours post-lymphocyte stimulation.
Main Results:
- A significant increase in micronucleus frequency was observed at 72 and 96 hours post-therapy.
- The CREST+ (whole chromosome) micronuclei frequency significantly increased, suggesting aneugenic effects.
- CREST- (acentric fragment) micronuclei frequency did not significantly increase.
Conclusions:
- Dacarbazine treatment induces chromosome loss in lymphocytes of treated patients.
- Dacarbazine primarily acts as an aneugenic agent in vivo.
- A 48-hour culture time may be insufficient for detecting genotoxic effects.
