Role of H2O2 in RET/PTC1 chromosomal rearrangement produced by ionizing radiation in human thyroid cells..     ///    "Pretreatment of cells with catalase, a scavenger of H(2)O(2), significantly decreased RET/PTC1 rearrangement formation. "    ///    "Therefore, we investigated the implication of H(2)O(2) in the generation of RET/PTC1 rearrangement after X-ray exposure. "    ///    This study shows for the first time that H(2)O(2) is able to cause RET/PTC1 rearrangement in thyroid cells and consequently highlights that oxidative stress could be responsible for the occurrence of RET/PTC1 rearrangement found in thyroid lesions even in the absence of radiation exposure..     ///    "Finally, RET/PTC chromosomal rearrangement was detected in HTori-3.1 cells after exposure of cells to H(2)O(2) (25 micromol/L), at a dose that did not affect the cell viability. "    ///    "By using the human thyroid cell line HTori-3, previously found to produce RET/PTC1 after gamma-irradiation, we showed that H(2)O(2), generated during a 5 Gy X-ray irradiation, causes DNA double-strand breaks and contributes to RET/PTC1 formation. "