Expression of SIRT1 and cortactin is associated with progression of non-small cell lung cancer.

Cortactin is an F-actin binding protein involved in cell migration and tumor metastasis. Recent reports suggest that silent mating-type information regulation 2 homologue 1 (sirtuin1; SIRT1) enhances the function of cortactin and promotes cell migration. We investigated SIRT1 and cortactin expression in 144 invasive non-small cell lung cancers (NSCLC) and 19 adenocarcinomas in situ (AIS) by immunohistochemistry and evaluated their clinicopathological significance in NSCLC. Positive SIRT1 and cortactin expression was observed in 67% (96 of 144) and 58% (84 of 144) of patients with invasive NSCLC, respectively. SIRT1 and cortactin expression was significantly associated with unfavorable clinicopathological factors, including high pathological T stage, lymph node metastasis, and advanced tumor invasion (AIS vs. invasive adenocarcinoma). Cortactin was significantly associated with high pathological T stage and lymph node metastasis in SIRT1-positive tumors. Cytoplasmic SIRT1 was significantly associated with high pathological T stage and large tumor size compared to that of nuclear SIRT1. Large tumor size, high pathological T stage, lymph node metastasis, and cytoplasmic SIRT1 expression were significantly associated with shorter overall survival in a univariate analysis. Our findings suggest that SIRT1 and cortactin may play a role in the progression of NSCLC and may cooperate during tumor progression in NSCLC.