Chemokines and their receptors in esophageal cancer--the systematic review and future perspectives.

Esophageal cancer (EC) is an aggressive malignant solid tumor with rapid progression and unfavorable prognosis. The 5-year survival rate for EC patients was estimated to be less than 10 %. Therefore, there is an urgent need to improve diagnostic tool and effective treatment therapies for EC patients. In our paper, the general structure and function of chemokines and their receptors as well as their role in cancer progression were shortly presented. Moreover, the aim of our paper was to summarize and refer the current findings concerning the role of selected chemokines and their receptors as candidates for tumor markers of EC. Some clinical investigations have proved the involvement of these proteins in proliferation, migration, invasiveness and metastasis of tumor cells. Increasing evidence from previous studies suggested that C-X-C motif chemokine 12 (CXCL12), also known as stromal cell-derived factor 1 (SDF-1) and its receptor CXCR4 may provide novel diagnostic and prognostic strategies to reduce the burden of EC. Moreover, therapy targeting the CXCL12/CXCR4 axis may open a new direction for treatment of EC patients. However, given their nonspecific nature, the diagnostic value of chemokines and their receptors may be limited. Therefore, future larger investigations, especially in the blood of EC patients, still need to be continued to further clarify the significance of these proteins as potential candidates for tumor markers in diagnosis and prognosis of EC patients.