Background: TCF-4 is an important downstream molecule of Wnt signaling pathway, but studies on the expression level and significance of TCF-4 in lung cancer were still limited. The aim of this study is to examine the expression level of TCF-4 in lung cancer tissues and cell lines, and analyze its relationship with clinicopathologic characteristics and biological behavior of lung cancers.
Methods: TCF-4 expression was examined in 120 lung cancer specimens and 10 corresponding normal lung specimens using immunohistochemistry (S-P method). Immunofluorescence was used to examine the TCF-4 protein expression level and subcellular localization in lung cancer cells and HBE (human normal bronchi epithelium) cells. Expression levels of TCF-4 mRNA were examined using transcription-polymerase chain reaction (RT-PCR) in 9 lung cancer cell lines.
Results: Among 120 lung cancer specimens, 96 samples showed high expression of TCF-4 (80.0%), including 37 samples showed TCF-4 expression both in cytoplasm and nuclei (30.8%),TCF-4 were not detected in 10 corresponding normal lung specimens. TCF-4 expression level was positively correlated with TNM stages (P =0.022). The fluorescence signal of TCF-4 protein was conspicuous in lung cancer cells, primarily in cell nuclei, but extremely low in HBE. TCF-4 mRNA expression levels were incompatible in different histology types, the expression level of TCF-4 was relatively high in giant cell carcinoma cells, but low in lung adencarcinoma cells.
Conclusions: High expression of TCF-4 positively correlated with lung cancer progression.