Doublecortin and CaM kinase-like-1 expression in pathological stage I non-small cell lung cancer

Purpose Doublecortin and CaM kinase-like-1 (DCLK1) regulates microtubule polymerization in migrating neurons. Recently, DCLK1 has been reported to act as an intestinal tumor stem cell marker and has been shown to be expressed in cancer cells and in the stroma of breast, colon, pancreatic, and prostate cancers. Here, we studied DCLK1 expression in non-small cell lung cancer (NSCLC) by immunohistochemistry in association with clinicopathological factors and patient prognosis. Methods DCLK1 expression was analyzed by immunohistochemical staining of surgical specimens from 232 patients with pathological stage I NSCLC, including 187 adenocarcinomas. Relationships between the expression status of DCLK1 and clinicopathological factors were examined. The impact of DCLK1 expression status and other clinicopathological factors on survival was evaluated by univariate and multivariate analyses. Results Thirty-three (14.2%) of 232 patients had DCLK1-positive cancer cells. DCLK1 was also expressed in the tumor stroma in most of the specimens and was significantly associated with DCLK1 expression in cancer cells. DCLK1-positive cancer cells were more common in non-adenocarcinoma tissues (44.4%) than in adenocarcinoma tissues (7.0%). Moreover, positive DCLK1 expression in cancer cells and stromal cells was correlated with a worse prognosis. Histological analyses revealed that the presence of DCLK1-positive cancer cells was an independent risk factor for poor prognosis in adenocarcinoma, but was not significantly associated with prognosis in non-adenocarcinoma. Conclusions DCLK1 expression was observed in tumor cells in patients with pathological stage I NSCLC and was correlated with adverse prognosis, especially in patients with adenocarcinoma. DCLK1 may be a potential new therapeutic target.