Possible transient adaptive response to mitomycin C in peripheral lymphocytes from thyroid cancer patients after iodine-131 therapy
✍ Scribed by Octávia Monteiro Gil; Nuno Guerreiro Oliveira; António Sebastião Rodrigues; António Laires; Teresa Cruz Ferreira; Edward Limbert; José Rueff
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- French
- Weight
- 128 KB
- Volume
- 102
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
Abstract
Our study attempted to assess the possible induction and persistence of an adaptive response in lymphocytes of thyroidectomized thyroid cancer patients treated with ^131^I (2,590 MBq, corresponding to whole body doses in the range of 200–300 mGy), to a testing dose of mitomycin C (MMC) in vitro. The cytogenetic endpoint studied was the induction of micronuclei in cytokinesis‐blocked peripheral blood lymphocytes, immediately before treatment and 1, 6 and 24 months after therapy. One month after therapy, induction of micronucleated cytokinesis‐blocked lymphocytes (‰) by MMC was lower (34.6 ± 7.7) than before therapy (52.1 ± 5.0). In 7 of 11 patients this reduction was significant. However, at 6 months, induction of micronuclei was markedly higher (133.1 ± 13.6). This significant increase was observed regardless of the decrease at 1 month. At 24 months, the frequency of micronucleated cells decreased (84.8 ± 5.5), but remained higher than before treatment. The results obtained 1 month after therapy could reflect adaptation due to radiation, or a higher rate of early apoptosis or cell death, with bone marrow suppression, visible as a lower response in vitro towards MMC. At 6 months, recovery of the lymphocyte population may occur, and higher responses to MMC in vitro could reflect higher chromosomal instability in the previously irradiated stem cells with a concomitant disappearance of adaptation, whereas at 24 months the results show a tendency to return to pretherapy values. © 2002 Wiley‐Liss, Inc.