IDO1, REST, NCOA2, EEA1, CLL19, and ALDH2 showed a positive correlation with immune infiltrates, while SLC7A5, SLC3A2, LDHB, and HPRT1 showed a negative correlation with immune infiltrates in the HNSCC database (Figure 8A). This evidence concerns the gene SLC7A5 and head and neck squamous cell carcinoma.