DNA Double-Strand Break Analysis by γ-H2AX Foci: A Useful Method for Determining the Overreactors to Radiation-Induced Acute Reactions Among Head-and-Neck Cancer Patients

Survival Fraction at 2 Gy and γH2AX Expression Kinetics in Peripheral Blood Lymphocytes From Cancer Patients: Relationship With Acute Radiation-Induced Toxicities

“…In breast cancer patients, the percentage of residual damage 3 hours and 6 hours after irradiation of peripheral lymphocytes has been correlated with increased sensitivity to radiation therapy (14). Similarly, Goutham et al (15) showed that the amount of residual gH2AX foci correlated with increased early radiation toxicity in head and neck cancer patents. A study of a series of over-responding patients with prostate cancer treated with radiation therapy found that persistently high gH2AX levels 24 hours after ex vivo lymphocyte irradiation correlated with increased late tissue sequelae (16).…”

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

“…In another study, the mean number of gH2AX foci per cell analyzed in peripheral blood mononuclear cells (PBMCs) of breast cancer patients undergoing radiotherapy was significantly higher compared with untreated healthy controls with respect to the initial (30 min after 0.5 Gy of X-rays) and residual (24 h after exposure to 2 Gy X-rays) gH2AX foci, indicating potential use of gH2AX assay for screening radiosensitivity of breast cancer patients [66]. The level of gH2AX foci has also been previously measured to predict the side effects of radiotherapy among head and neck cancer patients [89]. Persistence of gH2AX was higher in lymphocytes of head and neck cancer patients compared with the untreated control group for up to 6 h after exposure to 2 Gy of X-rays [89].…”

“…The level of gH2AX foci has also been previously measured to predict the side effects of radiotherapy among head and neck cancer patients [89]. Persistence of gH2AX was higher in lymphocytes of head and neck cancer patients compared with the untreated control group for up to 6 h after exposure to 2 Gy of X-rays [89]. Thus gH2AX would be a useful measure to identify individuals' radiosensitivity in advance so that customized radiation therapy may be applied to avoid severe side-effects due to radiation therapy.…”

DNA Damage Response Assessments in Human Tumor Samples Provide Functional Biomarkers of Radiosensitivity

“…Microscopic foci analysis was confirmed as the method of choice by comparing three different methods (foci, comet, and neutral filtration assay) to detect a γ-H2AX signal in ex-vivo irradiated (2 Gy) PBLs from 54 HNSCC patients receiving radiation/chemotherapy. The foci assay could best detect a correlation of γ-H2AX signal and acute oral mucositis and dermatitis (grade ≥3) 123 . In two studies with 41 and 47 pediatric solid tumors and leukemia patients receiving DNA-damaging therapy, γ-H2AX foci were evaluated in ex-vivo irradiated PBL which enabled the identification of patients at risk for high-grade acute and late toxicities and allowed for detection of DSB repair deficiencies, although not all treatment-associated normal-tissue toxicities could be explained by DSB repair insufficiencies 124 , 125 .…”