Identification of trophinin as an enhancer for cell invasion and a prognostic factor for early stage lung cancer

The explosion of microarray studies has promised to shed light on the identification of disease markers. To find novel prognostic factors, we used the expression profile of a poor prognostic factor of lung cancer, survivin (BIRC5), as a template to search for and compare transcriptome expression profiles in a lung adenocarcinoma microarray dataset. Trophinin (TRO) was identified as one of the best-correlated genes. The trophinin expression in lung cancer specimens was examined by immunohistochemical staining. The role of trophinin in cancer metastasis was further investigated by approaches of overexpression and knock down with small interfering RNA (siRNA). For stage I lung adenocarcinoma, the patients without trophinin expression had a better overall and disease-free survival. Overexpression of trophinin increases cell invasion ability and knock down with siRNA inhibits cell invasion. Through a combination of data mining and biochemical assays, we identified trophinin, which could enhance cell invasion, as a novel prognostic factor for early stage lung cancer.