One study established a mast cell gene-based signature for HNSCC to predict the prognosis and immunotherapeutic response.[28] Consistent with these previous reports, we found that HOXB9 expression was positively correlated to the infiltration of mast cells, indicating that the prognostic differences between the HOXB9high and HOXB9low groups can be attributed to immune regulation. Here, HOXB9 is linked to head and neck squamous cell carcinoma.