Doublecortin like Kinase-1 is Overexpressed in Breast Cancer Tissues and Correlated with Epithelial-mesenchymal Transition Markers

Background: Much of the current literature support, the idea that epithelial to mesenchymal transition (EMT) is the key mechanism by which tumor cells gain invasive and metastatic ability, as EMT enables separation of individual cells from the primary tumor mass as well as promote migration. After undergoing EMT, thereby enabling access to hematogenous or lymphatic routes of dissemination, tumor cells can extravasate into secondary organs and establish micro-metastases. Objective: The main target of this work was to study the relation between expression of Doublecortin-like kinase-1 (DCLK-1) and epithelial to mesenchymal transition markers (E-cadherin, vimentin and transforming growth factor-beta (TGF-β)) in breast cancer patients and assess its role in cancer prognosis. Materials and Methods: This study included 60 breast cancer patients and 40 healthy females as control group. Tumor tissues and adjacent normal breast tissues were collected from patients with breast cancer. A single venous blood sample was collected concurrently from breast cancer patients (Before surgery) and from the control group. Tissue expression of DCLK-1, E-cadherin and vimentin were evaluated in breast cancer tissues and normal breast tissues by real-time reverse transcription polymerase chain reaction (RT-PCR). Serum level of TGF-β was assayed by enzyme linked-immunossorbant assay. Results: According to the results of the present study DCLK-1 is highly expressed in breast cancer tissues compared to normal breast tissues. Overexpression of DCLK-1 was significantly correlated with higher tissues Vimentin expression, increased serum TGF-β and lower tissues E-cadherin expression. Kaplan-Meier survival curves for breast cancer patients revealed that, patients with elevated tissue DCLK-1 and Vimentin expression and higher serum TGF-β were significantly associated with poor prognosis in primary breast cancer patients. However, patients with lower tissue E-Cadherin expression had shorter disease free survival time than patients with higher levels. Conclusion: DCLK-1 was significantly increased in breast cancer tissues in comparison to normal breast tissues and its overexpression was significantly correlated with EMT markers and poor prognosis in breast cancer patients. Further prospective studies using greater numbers of patients are required to confirm our findings.