Chemoradiotherapy and Lymph Node Metastasis Affect Dendritic Cell Infiltration and Maturation in Regional Lymph Nodes of Laryngeal Cancer

Dendritic cells (DCs) are the most specialized antigen-presenting cells and lymph nodes (LNs) play an important role in the DC-mediated T-cell response. We evaluated the infiltration of CD1a-positive DCs (CD1a-DCs) i.e. immature DCs, and S100-positive dendritic cells (S100-DCs), a mixture of immature- and mature DCs, in 73 cases of laryngeal cancer and its regional LNs. Among them, 31 patients underwent radiotherapy (RT) or chemoradiotherapy (CRT) prior to surgery. No significant difference was found for CD1a-DC infiltration in the primary tumor, metastatic LNs and non-metastatic LNs, while S100-DCs were significantly fewer in number in the primary tumor and metastatic LNs compared to non-metastatic LNs. Cases which showed a high infiltration of S100-DCs in metastatic LNs appeared to show a favorable prognosis although statistical significance was not reached. In the RT/CRT group, infiltration of CD1a-DCs and S100-DCs were fewer in the primary tumor and metastatic LNs compared to the treatment naive group. Conversely, the RT/CRT group showed higher CD1a-DCs and S100-DCs numbers in non-metastatic LNs compared to the treatment naïve group. Thus, DC maturation in metastatic LNs plays an important role in tumor immunity in laryngeal cancer, and infiltration of DCs into the primary tumor and metastatic LNs is impaired by RT/CRT.