In thyroid cancer, high γH2AX expression was detected in 109 of 153 (71.2%) cancer tissues and 9 of 153 (5.9%) normal adjacent tissues, with statistical significance (P < 0.001), while high ATM expression was detected in 53 of 153 (34.6%) cancer tissues and 9 of 153 (5.9%) normal adjacent tissues, with statistical significance (P < 0.001). This evidence concerns the gene ATM and thyroid cancer.