In addition, by performing fluorescence-activated cell sorting (FACS) analysis, we confirmed that collagen treatment increased the number of both FOXP3+CD25+ Tregs and LAIR2+FOXP3+CD25+ Tregs obtained from the PBMCs in the HNSCC patients (Fig. 6g, h, and Supplementary Fig. 13c, and “Methods”). Here, FOXP3 is linked to head and neck squamous cell carcinoma.