RESUMEN
<p><b>BACKGROUND</b>The conformation of a subset of phosphorylated serines or threonines preceding proline motifs is regulated by the prolyl isomerase Pin1. Pin1 plays a critical role in oncogenesis. The aim of this study is to explore the relationship between the expression of Pin1 and clinicopathological factors in squamous cell carcinoma and adenocarcinoma of the lung, and to analyze the correlation between Pin1 and β-catenin.</p><p><b>METHODS</b>The expression of Pin1 and β-catenin proteins was detected in 69 lung cancer cases by immunohistochemical SP method, and in 30 fresh lung samples by Western blot.</p><p><b>RESULTS</b>Immunohistochemically, the overexpression of Pin1 and β-catenin in lung cancer was 78.3% (54/69) and 63.8% (44/69), respectively. The expression of Pin1 and β-catenin was not related to age, sex, histological classification, differentiation, lymph node metastasis and pTNM stages. There was a positive correlation between overexpression of Pin1 and aberrant β-catenin expression (P < 0.05). Western blot results showed that the expression of Pin1 and β-catenin in lung cancer tissues was significantly higher than that of paracancerous lung tissues (P < 0.05).</p><p><b>CONCLUSIONS</b>Pin1 is overexpressed in squamous cell carcinoma and adenocarcinoma of the lung and may play a critical role in oncogenesis of lung cancer. Overexpression of Pin1 might contribute to the upregulation of β-catenin and it may be one of the pathways for Pin1 to work.</p>