ATM and rectal cancer: Fig 1A shows representative immunohistochemical staining of high and low/absent ATM and MRE11 expression in rectal cancer tissues. Results from the combined marker analysis differed from our initial single biomarker studies of ATM and MRE11 alone, in that a high combined expression of ATM and MRE11 was significantly associated with a number of clinicopathological variables. These included neoadjuvant status (P = 0.001 for TC), TRG (P = 0.03 for TC, P = 0.011 for TP), age (P = 0.02 for TP), and nodal stage (P = 0.042 for TP) (Table 2).