Head and neck cancer (HNC) is the sixth among the top ten cancers in the world. Among this group of disease, oral cancer has been one of the top five killers in males for many years in Taiwan. Despite combined treatment, the prognosis for HNC patients is, in general, poor, which has strongly stimulated research on finding new strategies specific for HNC. To find a new treatment protocol for HNC, we examined the tumor microenvironment of a carcinogen (4-Nitroquinolone-1-oxide,4-NQO)-induced oral cancer. The immunohistochemical staining (IHC) results showed that this tumor has relative low density of vessels and high percentage of hypoxia around tumor edge. In addition, we found a layer of α-SMA positive cancer-associated fibroblast (CAF) in the junction of tumor and normal tissues. Further, we also found that a cluster of high density of CD68+ macrophages and Gr-1+ cells in this junction. To our surprise, very few tumor-associated macrophages (TAMs) could be identified in other tumor regions except this junction. In addition, the analysis of blood sample during tumor development found that the population of monocytic and granulocytic myeloid-derived suppressor cells (M-MDSCs and G-MDSCs) in the whole blood increases with the growth of the tumor, which has good correlation with the decrease of CD8+ and CD4+ T cells. The unique spatial distribution of myeloid cells in tumor tissue and consistent dynamic change of MDSC and T cells in the blood provides us an ideal tumor model for designing new strategies specific for HNC. We are currently using this tumor model to study the potential of combining immunotherapy with boron neutron capture therapy (BNCT) for HNC.

Citation Format: Chi Jui Chen. Time and spatial distribution of monocytic lineages in the process of carcinogen-induced oral cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1102.