Prediction of late normal tissue complications in RT treated gynaecological cancer patients: Potential of the γ-H2AX foci assay and association with chromosomal radiosensitivity

Abstract

Abstract. In the present study, the Á-H2AX assay was investigated as a predictive test for the development of late normal tissue complications. Therefore, phosphorylated histone H2AX (Á-H2AX) foci were scored in peripheral blood T-lymphocytes of gynaecological radiotherapy patients, irradiated in vitro with a high dose rate (HDR) and a low dose rate (LDR) protocol. The G 2 chromatid break assay was used to compare chromosomal radiation sensitivity with DNA doublestrand-break (DSB) repair capacity. Late normal tissue reactions were scored according to the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 scale. In our analyses, no differences in foci kinetics were found between the non to mild and moderate to severe patient groups after HDR irradiation. Furthermore, no relation was observed between the level of residual Á-H2AX foci and CTC score after LDR irradiation. On the contrary, the number of chromatid breaks was associated with late clinical radiation sensitivity. Comparison of G 2 chromatid break assay data with the residual number of radiationinduced foci after LDR irradiation and repair times after HDR irradiation showed no relationship between the assays. From this study we can conclude that scoring of Á-H2AX foci after in vitro irradiation of isolated T-lymphocytes of patients is not predictive for late radiotoxicity. This applies as well to the assessment of the repair kinetics after an HDR dose as to the determination of the number of residual foci after a LDR dose.

Persistent γH2AX: A promising molecular marker of DNA damage and aging

“…Persistence of gH2AX was also significantly higher in lymphocytes of Shwachman-Diamond syndrome individuals (an autosomal-recessive disorder characterized by bone marrow failure and a cumulative risk of progression to acute myeloid leukemia) compared to shamirradiated cells 4 h after exposure to 4 Gy and 10 Gy of X-rays or g-rays [90]. Interestingly, another group [84] found no difference in the persistence of gH2AX foci in T-lymphocytes 24 h after ex vivo exposure (up to 2.2 Gy) when comparing (1) none to mild and Table 1 Persistent gH2AX response among animals in different cell and tissue types following ionizing radiation. Visually scored using fluorescence images [118] (2) moderate to severe, late normal tissue radiotoxicity in gynecological cancer patients [84].…”

“…Interestingly, another group [84] found no difference in the persistence of gH2AX foci in T-lymphocytes 24 h after ex vivo exposure (up to 2.2 Gy) when comparing (1) none to mild and Table 1 Persistent gH2AX response among animals in different cell and tissue types following ionizing radiation. Visually scored using fluorescence images [118] (2) moderate to severe, late normal tissue radiotoxicity in gynecological cancer patients [84]. Persistent gH2AX was assessed in T lymphocytes from Ataxia Telangiectasia (AT) patients and patients with Nijmegen breakage syndrome (NBS), a disease associated with the mutation in nibrin proteins (coded by NBN gene).…”

“…Radiation therapy used in cancer treatment is applied either alone or in combination with chemotherapy; however, radiation therapy induces severe side-effects (acute effects such as erythema, edema, mucositis, dry or moist desquamation, severe skin changes, and late effects such as telangiectasia, fibrosis, cancer induction, brachial plexopathy, neurological effects) due to normal tissue toxicity (NTT) [81][82][83][84][85]. NTT has been graded by the Radiation Therapy Oncology Group into a standardized scale of acute and late responses after radiotherapy treatment for all tissue types, and these scales are used to avoid severe sequelae of radiotherapy [86].…”

Lack of a correlation between γH2AX foci kinetics in lymphocytes and the severity of acute normal tissue reactions during IMRT treatment for head and neck cancer

“…In order to work with a homogenous cell population, T-lymphocytes were separated from the lymphocyte pool using the RosetteSep Human T cell Enrichment Cocktail (StemCell Technologies, Grenoble, France). The T-lymphocyte isolation was performed using the protocol as described previously (Werbrouck et al 2010). Cells were incubated overnight in a humidified 5% CO 2 atmosphere at 378C (Thermo Scientific, Erembodegem, Belgium).…”

Deoxyribonucleic acid damage-associated biomarkers of ionising radiation: current status and future relevance for radiology and radiotherapy

“…g-H2AX measurement by flow cytometry has been shown by Bourton et al [108] to be a possible marker capable of predicting the risk of radiotherapy patients developing excessive normal tissue toxicity and to a lesser degree that may be used for the prediction of oral mucositis [109]. However, other studies show no correlation between g-H2AX foci and acute [110] or late tissue damage [111]. Scoring of chromosome aberrations in ex vivo-irradiated lymphocytes has also been correlated with acute and late normal tissue damage in radiotherapy patients [112,113].…”