As shown in Supplementary Figure S1C and Supplementary Table S1, we found that RAC1-amp/gain status (vs. RAC1-diploid status) remained significantly associated with poorer OS (p = 0.0080 **, log-rank test) and DFS among HPV(−)HNSCC patients (p = 0.0403 *, log-rank test), whilst RAC1-amp/gain status was not associated with OS nor DFS among HPV(+)HNSCC patients (p = 0.3053, Supplementary Table S1). The gene discussed is RAC1; the disease is head and neck squamous cell carcinoma.