Background: The aim of this work was to determine whether levels of radiation-induced apoptosis in human peripheral leukocytes could be used as a predictor of radiosensitivity. Materials and Methods: Peripheral blood was obtained from venous blood and exposed to 0-3 Gy of X-rays. Apoptosis levels were measured at 4, 24, 48 and 72 hours after exposure using the neutral comet assay. Intra-individual apoptotic response was measured using repeated blood samples from four healthy individuals. Inter-individual variation was investigated in whole blood, granulocytes and mononuclear cells from 8 radiotherapy patients (4 demonstrating a radiosensitive response and 4 demonstrating a normal response to radiation exposures). Results: Amongst the four healthy individuals there was both inter- and intra-individual variation of about the same magnitude. However, when comparing the apoptotic response of the radiosensitive and normal patients, consistent trends were observed at all X-ray doses for all of the patients. Conclusion: This indicates that apoptosis has some potential as a predictive assay, however, large intra-individual variation exists. More studies are required to investigate the causes of intra-individual variation and how it might be minimized.

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Keywords Apoptosis, Comet assay, Human blood, Predictive assay, Radiation
Journal Anticancer Research
Kizilian-Martel, N. (N.), Wilkins, R.C, McLean, J.R.N. (J. R.N.), Malone, S. (S.), & Raaphorst, G.P. (G. P.). (2003). Prediction of Radiosensitivity by Measurement of X-ray-induced Apoptosis in Human Blood using the Comet Assay. Anticancer Research, 23(5 A), 3847–3854.