Are thyroid cancer patients sensitive to ionising radiation?
ABSTRACT To determine the ionising radiation sensitivity of peripheral blood lymphocytes in a group of differentiated thyroid cancer (DTC) patients.
A total of 53 thyroid cancer patients (26 women and 27 men) and 50 donors (23 women and 27 men) were included in the study. The cytokinesis-block micronucleus assay (CBMN) in G0 peripheral blood lymphocytes was carried out using the cytochalasin B technique. Four cultures were established per each donor, two were irradiated with 0.5 Gy 137Cs g-rays, while the other two remained untreated.
No significant differences were observed in the frequency of binucleated cells with micronuclei (BNMN) between patients and controls, for both spontaneous and after the irradiation frequencies. Nevertheless, a positive and significant correlation was found between the frequencies of both spontaneous and after irradiation DNA damage, for control and patient groups.
We have found that DTC patients do not present particular sensitivity to ionising radiation when an in vitro treatment is performed in G0 stage of the cell cycle, but this result does not discard the hypothesis about an increased sensitivity in other stages of the cell cycle in DTC patients.
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ABSTRACT: Short title: Genetic variants at TPO and thyroid cancer risk Thyroid cancer risk involves the interaction of genetic and environmental factors. The thyroperoxidase (TPO) has a key role in the iodine metabolism, being essential for the thyroid function. Mutations in the TPO gene are common in congenital hypothyroidism, and there are also signs of the implication of TPO in thyroid cancer. We performed a case-control association study of genetic variants in TPO and differentiated thyroid carcinoma (DTC) in 1586 DTC patients and 1769 controls including two European populations (Italy: 1190 DTC and 1290 controls; Spain: 396 DTC and 479 controls). Multivariate logistic regression analyses were performed separately for each population and each SNP. From the three studied polymorphisms significant associations were detected between DTC and rs2048722 and rs732609 in both populations (P<0.05). In the Italian population both SNPs showed a negative association (rs2048722, OR=0.79, 95% CI=0.63-1.00, P=0.045; rs732609, OR=0.72, 95% CI=0.55-0.94, P=0.016), while in the Spanish population these SNPs showed a positive association (rs2048722, OR=1.39, 95% CI=1.03-1.89, P=0.033; rs732609, OR=1.41, 95% CI=1.06-1.87, P=0.018). The corresponding associations for papillary or follicular thyroid cancer were similar to those for all DTC, within population. No association was detected for the third TPO polymorphism in the Italian and the Spanish populations. Our results, for the first time, point to TPO as a gene involved in the risk of DTC, and suggest the importance of interactions between TPO variants and other unidentified population-specific factors in determining thyroid cancer risk. © 2013 Wiley Periodicals, Inc.International Journal of Cancer 06/2013; · 6.20 Impact Factor