KRAS and neoplasm: We then performed multivariate reverse stepwise Cox regression modelling (with a threshold for removal from the model of p>0.05) for each of g-H2AX, ATM and Ku70, including as co-variates age, gender, Dukes stage, tumour location, trial arm (rofecoxib vs. placebo), chemotherapy status, radiotherapy status, CIN, KRAS and BRAF mutation status and MSI (Table 2).