ATM expression was initially scored as the product of percentage and intensity of staining based on Angele et al . The percentage of positive staining was scored as: 1, <25%; 2, 25%–50%; 3, 50%–75%; or 4,>75%. The intensity of staining was graded as: null, 0; low, 1; moderate, 3; or high, 5. The two scores were multiplied to create a composite score between 0 and 20 and analyzed against clinicohistopathological and clinical outcome data. The percentage of MRE11-positive cells and staining intensity were also scored using the methods published previously . Intensity was graded as: negative, 0; weak, 1; moderate, 2; or strong, 3. The percentage of positive cells was graded as: 0, <5%; 1, 5%–25%; 2, 26%–50%; 3, 51%–75%; and 4, >75%. These two measures were multiplied to give weighted scores ranging from 0–12. To combine the two proteins as a biomarker panel, all cases were categorized into either a low expression group (score range: 0–5) and a high expression group (score range: 6–32).