In addition, Spearman’s correlation coefficient analysis between copy number variants and gene expression was performed, and it was found that copy number variants of KIRK1 and FASLG were down-regulated in HNSCC, while LAMP1, SH3BP2, MAP2K1, PGM3, PIK3R2, BID, ULBP1, PVR, and KIR3DL2 were up-regulated (Supplementary Figure 3D). Here, PIK3R2 is linked to head and neck squamous cell carcinoma.