Neutralization of PDGF resulted in a >50% reduction in 3/3 HNSCC cell lines with a near complete arrest of MSC chemotaxis in 2/3 HNSCC cell lines (Fig. 5b; *p < 0.0001) whereas neutralization of IL-6 resulted in a ~50% reduction in MSC chemotaxis in 1/3 cell lines (Fig. 5c; *p < 0.0001, **p < 0.03). The gene discussed is IL6; the disease is head and neck squamous cell carcinoma.