It has also been shown that in some tumours NF-κB activation can enhance radiosensitivity.6,7 Preoperative radiotherapy (RT) is today a standard treatment for rectal cancer patients in Sweden and other countries.8 It has been shown to increase survival of the patients.9,10 In the present study, we investigated whether the phospho-Ser536-p65 was related to response of RT in rectal cancer patients who received or did not receive RT, and whether there were any relationships of the phospho-Ser536-p65 with clinicopathological variables and biological factors. This evidence concerns the gene NFKB1 and neoplasm.