Prolonged expression of the y- XXXX DNA repair biomarker correlates with excess acute and chronic @entity137 from radiotherapy treatment.

@entity1 @entity6714 @entity137 @entity5
The normal tissue tolerance levels to fractionated radiotherapy have been appreciated by a century of careful clinical observations and radiobiological studies in animals. During clinical fractionated radiotherapy, these normal tissue tolerance levels are respected, and severe sequelae of radiotherapy are avoided in the majority of @entity1 . Notwithstanding, a minority of @entity1 experience unexpectedly severe normal tissue reactions. The ability to predict which @entity1 might form this minority would be important. We have conducted a study to develop a rapid and reliable diagnostic test to predict excessive normal tissue @entity137 (NTT) in radiotherapy @entity1 . A flow cytometric immunocytochemical assay was used to measure DNA damage in peripheral blood lymphocytes (PBL) from @entity5 @entity1 exposed to 2-Gy gamma radiation. DNA damage and repair was measured by induction of cellular y- @entity6714 in unirradiated and exposed cells at specific time points following exposure. In 12 @entity5 @entity1 that experienced severe @entity137 following radiotherapy, there was a failure to repair DNA double-strand breaks (DSB) as measured by y- @entity6714 induction and persistence. In ten @entity5 @entity1 that experienced little or no NTT and in seven normal (noncancer controls), efficient repair of DNA DSB was observed in the y- @entity6714 assay. We conclude that a flow cytometric assay based on y- @entity6714 induction in PBL of radiotherapy @entity1 may represent a robust, rapid and reliable biomarker to predict NTT during radiotherapy. Further research is required with a larger @entity1 cohort to validate this important study.
