The prognostic significance of immunohistochemically detected p53 protein expression in non-small cell lung cancer treated with radiation therapy

The prognostic significance of nuclear p53 protein expression in survival a nd local control was investigated immunohistochemically in 36 patients with inoperable or unresectable non-small cell lung cancer who were treated wit h radiation therapy (RT). Formalin-fixed, paraffin-embedded sections obtain ed by bronchoscopy were used to examine the expression of nuclear p53 prote in with immunohistochemistry. In 25 cases (69%), p53 protein expression was detected: There was no relation between p53 expression and other pretreatm ent characteristics. Response to RT was found in all p-53 negative cases ve rsus 72% in p53-positive cases (p<0.05). The 2-year survival rate for p53-n egative cases was 51% with a median survival time of 21 months. The corresp onding rate for p53-positive cases was 31% with a median survival time of 9 months. This difference, however, did not reach a statistically significan t level because of the small sample size. In conclusion the results of this study suggest that p53 protein expression may be of predictive value on re sponse to RT in non-small cell lung cancer.