Nuclear Factor-kB (NF-kB) Is Frequently Expressed in Lung Cancer and Preneoplastic Lesions

BACKGROUND. Nuclear factor-kB (NF-kB), a key transcription factor thought to play a major role in carcinogenesis, regulates many important signaling pathways involved in tumor promotion. Although NF-kB can be activated in lung cancer cell lines by tobacco exposure, there have been no studies of the expression of NF-kB in lung cancer pathogenesis. METHODS. The immunohistochemical expression of NF-kB p65 was investigated in 394 lung cancers (370 nonsmall cell lung carcinomas [NSCLC]; and 24 small cell lung carcinomas [SCLC]) and 269 lung normal epithelium and preneoplastic lesions, including hyperplasias, squamous metaplasias, dysplasias, and atypical adenomatous hyperplasias. RESULTS. High levels of nuclear immunohistochemical expression of NF-kB p65 were detected in the lung cancers, with significantly higher levels in SCLCs com-pared with NSCLCs (P <.0001). In adenocarcinomas the NF-kB p65 expression level was significantly higher in advanced TNM stages (III-IV) than in earlier stages (I-II) (P <.0001), and when NF-kB p65 is dichotomized using 50 % as the cutof