EGFR and head and neck squamous cell carcinoma: Total PBMC or purified monocytes from HNSCC patients with new active diseases (n = 9) were co-cultured with PCI15B or JHU029 (HNSCC cell lines with high EGFR expression) for 3 days with 10 μg/mL cetuximab or hIgG1 (isotype control), before analysis of surface markers on CD14+ monocytes by flow cytometry.