BACKGROUNDIt has been known that the expressions of β-catenin and T cell factor 4 (TCF-4) were associated with clinicopathological parameters in non-small cell lung cancer (NSCLC). The objective of this study is to explore the relationship between expressions of β-catenin and TCF-4 in NSCLC.

METHODSThe expression of β-catenin was detected with immunohistochemistry in 100 lung cancer samples; the relationship between abnormal located and preserved β-catenin with TCF-4 was investigated by immunofluorescence, co-immunoprecipitation and hybridization in situ.

RESULTSThe levels of protein and mRNA were both significantly higher in NSCLC than in corresponding normal lung tissues. Aberrant cytoplasmic and/or nuclear expression of β-catenin were 78.74% (100/127) while aberrant nuclear expression was 37.01% (47/127). Aberrant nuclear β-catenin was significantly associated with differentiation (P=0.0008) and lymphatic metastasis (P=0.017). Positive TCF-4 expression (86.67%, 52/60) was normally seen in nucleus and cytoplasm of cancer cells. The intensity of TCF-4 expression was significantly higher in moderately and poorly differentiated lung cancers than that in well differentiated ones. In total 17 cases of β-catenin (+) and TCF-4 (+) patients, 13 cases were detected with the β-catenin/TCF-4 complex, 61.54% in nucleus and 38.46% in cytoplasm.

CONCLUSIONSThe abnormal mRNA and protein expressions of β-catenin are associated with malignant phenotype in NSCLC. TCF-4 expression is associated with poor differentiation in lung cancers. The β-catenin/TCF-4 complex exists widely in NSCLC.