High CCR6/CCR7 expression and Foxp3+ Treg cell number are positively related to the progression of laryngeal squamous cell carcinoma

Chemokine receptors CCR6 and CCR7 have been reported to play important roles in T cell migration and organ-specific metastasis of various tumors. In the present study, we evaluated the expression and clinical significance of CCR6, CCR7, their ligands and CD4(+)CD25(+)Foxp3(+) regulatory T cells in laryngeal squamous cell carcinoma (LSCC) and metastatic lymph nodes (LNs). The expression of CCR6, CCR7 and their ligands mRNA (CCL20, CCL19/CCL21) as well as the CCR6 and CCR7 proteins were detected by real-time RT-PCR and immunohistochemistry (IHC), respectively. Flow cytometry was used to investigate the percentage of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) in peripheral blood mononuclear cells (PBMCs). Furthermore, a number of cytokines, including interleukin (IL)-2, IL-4, IL-10, IL-12p70, interferon (IFN)-gamma and transforming growth factor (TGF)-beta 1 were detected by ELISA. The results showed that CCR6 and CCR7 were expressed in tumors in situ, metastatic LNs and CD4(+)CD25(+)Foxp3(+) Tregs. It was hypothesized that the expression profile of CCR6, CCR7 and the proliferation of CD4(+)CD25(+)Foxp3(+) Tregs affected the process of LN metastasis in LSCC patients. Therefore, the increased percentage of the Foxp3(+) Tregs and the upregulation of Foxp3 expression on CCR6(+) Tregs in LSCC patients may have accounted for the downregulation of antitumor immunity in these patients, which could be valuable for assessment of prognosis in LSCC treatment.