Resistance to radiotherapy often seen in rectal cancer patients requires intensive study of mechanisms taking part in this process. It seems that nuclear factor-kappaB (NF-κB), especially its subunit p65, could play an important role in radioresistance. The aims of this study were: 1. to assess expression of p65 in rectal cancer patients and to evaluate its possible predictive role; 2. to determine in in vitro experiments possibilities of p65 modulation and to evaluate, whether this modulation can result in enhacement of efficiency of radiation therapy. We found that the level of NF-κB expression may serve as a predictive marker of overall survival. Further we found that inhibition of NF-κB activity caused by radiation improves impact of radiation therapy.

        Key words: NF-kappaB – rectal cancer – radiotherapy – immunohistochemistry – marker