In order to further elucidate the potential connection between the induced CXCL4 secretion and the M2 polarizing impact of the corresponding exosomes of our HNSCC patient cohort, correlation analyses between measured CXCL4 (ng/ml) and expression levels of M2-like macrophage marker CD206 on monocyte derived M0/M1/M2 macrophages upon HNSCC exosome internalization were performed. Here, MRC1 is linked to head and neck squamous cell carcinoma.