Fig. 1

Circulating monocytic MDSC (CD11b⁺CD14⁺HLA-DR^lo/-) increased after cetuximab treatment in non-responders after cetuximab neoadjuvant therapy. Levels of monocytic MDSC (CD11b⁺CD14⁺HLA-DR^lo/-) in the peripheral blood of healthy donors versus HNSCC patients and HNSCC patients pre- and post-cetuximab treatment were analyzed by flow cytometry. a Representative figures showing frequency of CD14⁺HLA-DR^lo/- cells in CD11b⁺ mononuclear cells in peripheral blood from healthy donors and HNSCC patients. The mean LIN⁻CD11b⁺ cells from healthy donors and HNSCC patients were not statistically different. b Representative figures showing percentage of CD14⁺HLA-DR^lo/- cells in circulating CD11b⁺ cells from responders and non-responders of UPCI 08–013 trial before and after cetuximab treatment. c Summary data of frequency of CD14⁺HLA-DR^lo/- cells in CD11b⁺ PBMC or in total live PBMC pre- and post-cetuximab treatment in the total 40 HNSCC patients (left panel) and in responders (n = 10) and non-responders (n = 19) of UPCI 08–013 trial (right panel). Statistical significance was determined by Wilcoxon matched-pairs signed rank tests for the same patients pre- and post-cetuximab treatment and Mann Whitney test for baseline levels in responders versus non-responders. *p < 0.05