immature myeloid and plasmacytoid DCs in the LCT and PB of patients with various stages and grades of squamous cell carcinoma of the larynx (n=66) and PB of healthy donors

Despite improvements in immunotherapy, little is known about dendritic cell (DC) subpopulations naturally occurring in the laryngeal cancer tissue (LCT) and peripheral blood (PB) of untreated laryngeal cancer (LC) patients. The purpose of the present study was to evaluate mature, immature myeloid and plasmacytoid DCs in the LCT and PB of patients with various stages and grades of squamous cell carcinoma of the larynx (n=66) and PB of healthy donors (n=20), and to explore the correlation of the percentages of the DCs to clinical parameters. The percentage of DCs in LCT and PB was determined using monoclonal antibodies and flow cytometry. It has been revealed that DCs accumulate in LCT in comparison with their content in PB. The myeloid to lymphoid/plasmacytoid DC ratio was higher in LCT compared to PB. It was found that in cases of poorly-differentiated LC, there were higher percentages of lymphoid/plasmacytoid DCs in LCT in comparison to their content in the PB. Moreover, in the blood of patients with T4 cancers we found significantly lower percentages of myeloid DCs in comparison to individuals with T1 neoplasms. The percentage of myeloid DCs infiltrating cancer tissue positively correlated with the T stage. In patients with no metastases in the lymph nodes, PB contained less mature DCs but higher amount of myeloid DCs compared to LCT. Alteration of the DC proportion in LC patients may result in the development of immunotolerance.