Intra-tumoral immune cell composition is not heterogeneous in HNSCC

Introduction:

The head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent malignant disease worldwide. The current treatment includes surgery and/or radiation therapy, radiochemo- and antibody therapy. Immune cell infiltration is one important determinant of patient survival. Immunotherapy with checkpoint inhibitors gained growing interest in tumor therapy and immune cell infiltration may play a role for successful therapy. The focus of our study was to investigate the heterogeneity of immune cell infiltration in different regions of HNSCC biopsies. We focused on regulatory T cells, antigen presenting cells, and the expression of costimulatory as well as inhibitory molecules on tumor infiltrating T cells.

Methods:

We analyzed biopsies from different tumor regions and corresponding healthy mucosa of 30 patients by flow cytometry.

Results:

Comparing tumor tissue with corresponding healthy mucosa, we observed a significant decrease in the number of intra-tumoral CD4+ as well as CD8+ T cells while different types of myeloid cells, especially neutrohilic granulocytes, were massively increased. The comparison of the immune cell populations in different tumor regions, revealed no significant differences. Also the expression of activation markers (e.g. CD69) and checkpoint molecules (e.g. PD-1) on tumor infiltrating lymphocytes was not altered between biopsies from different localisations, also activation and distribution of myeloid cells showed no significant variation.

Conclusion:

In conclusion, our results show that HNSCC are characterized by a massive infiltration with neutrophilic granulocytes and low numbers of lymphocytes. This feature was similar between different tumor regions indicating no intra-tumoral heterogeneity in immune cell infiltration.

Publication History

Publication Date:
23 April 2019 (online)