Cytogenetic follow-up in testicular seminoma patients exposed to adjuvant radiotherapy.

Early stage testicular seminoma is a radiosensitive tumor. Its incidence has significantly increased during the last decade especially in the young population. Although the therapy for testicular seminoma gives very satisfying results, the evaluation of genome damage caused by the therapy is of a great importance in order to recognize possible related health risks. The present study was performed on ten patients diagnosed with seminoma stage I; pT1/2N0M0S0, treated with adjuvant radiotherapy (a radiation dose of 25 Gy divided in 16 fractions) after orchidectomy. To assess the possible existence of an increased baseline DNA/chromosome damage in patients we also selected the appropriate control group often healthy men. The levels of primary DNA/chromosome damage in peripheral blood lymphocytes, as well as the dynamics of their repair were studied using the alkaline comet assay, chromosome aberration and cytokinesis-block micronucleus assay. Altogether four blood samples per patient were collected in the course of the therapy: before and after receiving the first dose of radiotherapy, in the middle of the radiotherapy cycle, and after the last dose of radiotherapy. Other two follow-up blood samples were collected six and twelve months after the cessation of therapy. As observed, the administration of the first radiation dose significantly increased the levels of DNA damage in almost all patients compared to their baseline values. Specific patterns of DNA damage were recorded in samples analyzed in the middle of radiotherapy and after receiving the last dose, indicating the possibility of an adaptive response in some patients. The levels of chromosomal aberrations and the incidence of micronuclei also increased in the course of therapy but gradually declined during the follow-up period. Our results confirmed the existence of post-irradiation damage in peripheral blood lymphocytes (and possibly in other non-target cells) of cancer patients which may represent a risk for the secondary cancer development. Considering that the majority of patients with testicular cancer are of a younger age, they represent a population deserving special attention. As cytogenetic screening may detect high-risk individuals, it might be useful in regular medical monitoring of seminoma patients after the successful therapy.

DNA and cytogenetic damage in white blood cells of postmenopausal breast cancer patients treated with radiotherapy.

The primary and residual genome damage and its elimination rate were evaluated in peripheral blood lymphocytes of breast cancer patients treated with adjuvant radiotherapy after surgical removal of the tumor by mastectomy or quadrantectomy. The levels of DNA/chromosome damage were estimated before, throughout, as well as after six months, respectively one year after the radiotherapy, using the alkaline comet assay, the chromosome aberration analysis and the cytokinesis-block micronucleus assay. The marked individual differences in the baseline genome damage were observed in patients, which additionally increased until the end of the radiotherapy cycle. The levels of DNA/cytogenetic damage slowly declined during post-irradiation period; although in the majority of subjects they did not return to pre-therapy levels. In addition to the well-established comet parameters, the long-tailed nuclei were also proved as a useful indicator of individual DNA damage and response to radiation. One of the most important observation was that older breast cancer patients, irradiated after mastectomy, had higher values of almost all parameters evaluated. We found positive correlations between the comet assay parameters and the cytogenetic biomarkers that confirmed their complementary value in the assessment of the radiation sensitivity/susceptibility in elderly breast cancer patients. The specific patterns of DNA damage observed in the majority of subjects after a prolonged exposure to ionizing radiation indicate the possibility of adaptive response. Such results may also be linked to the hormesis theory and support previous observations, but the underlying mechanisms should be further investigated on a much larger population.

Evaluation of radioprotective effects of propolis and its flavonoid constituents: in vitro study on human white blood cells.

This in vitro study aimed to evaluate the possible radioprotective effects of the natural substances WSDP, caffeic acid, chrysin and naringin on gamma-irradiated human white blood cells. The effectiveness of tested compounds was evaluated using the alkaline comet assay, the analysis of structural chromosome aberration and the cytokinesis-block micronucleus assay. The results obtained by the alkaline comet study indicate favourable toxicity profiles of propolis and its polyphenolic components, and confirmed the radioprotective abilities comparable to the chemical radioprotector AET. WSDP and its polyphenolic components were able to reduce the number of necrotic cells. None of tested compounds induced significant genotoxicity, but all of them offered a quite measurable protection against DNA damage. WSDP was found to be the most effective in diminishing the levels of primary and more complex cytogenetic DNA damage in white blood cells. Considering its complex composition, to undoubtedly explain the underlying mechanisms of cyto/radioprotective effects, further studies are needed.

Evaluation of radioprotective effects of propolis and quercetin on human white blood cells in vitro.

This in vitro study aimed at investigating the possible radioprotective effects of natural substances propolis and quercetin on gamma-irradiated human white blood cells. The levels of primary DNA damage were studied by the alkaline comet assay, while the cytogenetic damage was evaluated using the analysis of structural chromosome aberration and cytokinesis-block micronucleus assay. The results obtained by all endpoints indicate acceptable toxicity profiles of propolis and quercetin in vitro, and also confirmed their radioprotective abilities. Propolis was found to be more effective in diminishing the levels of primary and more complex cytogenetic DNA damage in gamma-irradiated white blood cells. Data gathered in present study support the use of propolis and quercetin as non-toxic protective substances. However, to clarify the underlying mechanisms of their cyto/radioprotective activities, additional studies are necessary at both in vitro and in vivo levels.

Assessment of the radioprotective effects of amifostine and melatonin on human lymphocytes irradiated with gamma-rays in vitro.

Radioprotective effects of amifostine and melatonin as well as their ability to modulate the level of spontaneous and gamma-irradiation-induced genetic changes on human peripheral blood lymphocytes were investigated using the cytokinesis-block micronucleus (CBMN) assay and sister chromatid exchange (SCE). Parallel blood samples were pre-treated with amifostine, melatonin and their combination for 30 minutes. Negative controls were also included. After the treatment with radioprotectors, one blood sample of each experimental group was exposed to gamma-rays from a 60Co source. The radiation dose absorbed was 2 Gy. Our research confirmed the radioprotective effects of both chemicals in vitro, with no significant genotoxicity. Pre-treated irradiated blood samples showed a decrease in the total number of micronuclei (MN) and in the number of cells with more than one MN. They also showed significantly lower mean SCE values. This study shows that it is possible combine these radioprotectors by adjusting the doses of amifostine to achieve the best radioprotective effect with as few side effects as possible. However, further in vitro and clinical studies are needed to clarify their mechanisms of action and possible interactions.

Radiotherapy of stage IEA primary breast lymphoma: case report.

A 47-year-old woman was referred for the treatment to our Hospital because of a palpable nodule in the upper medial quadrant of her right breast. After tumor excision, pathohistological examination showed a follicular center cell lymphoma grade 2, B-cell type (CD20+, bc16+, CD10+, bcl2+). The final diagnosis was stage IEA primary extranodal non-Hodgkin s breast lymphoma. The involved breast was irradiated isocentrically with two opposite 6-megavolt (MeV) photon beams delivered from the linear accelerator (tangential fields) using asymmetric collimator opening. Radiation volume, inclinations of the medial and lateral field, and the part of the underlying chest wall and lung parenchyma were determined during the radiotherapy simulation process. The total irradiation dose was 44 Gy delivered in single daily doses of 2 Grays (Gy). After breast photon irradiation, a boost to the tumor bed was performed by a direct 12 MeV electron beam, with a total dose of 6 Gy delivered over three days. Since primary non-Hodgkin lymphoma of the breast is rather rare, there has been no uniform approach to its treatment. The advantage of applying the asymmetric collimator jaw opening in breast radiotherapy is the instant reduction of the dose at margin fields, resulting in both the protection of neighboring lung parenchyma and the good coverage of planned target volume.