STAT4 and head and neck squamous cell carcinoma: Future studies focused on potential causative factors underlying HNSCC tumor development and metastasis associated with STAT4 deficiency, as well as an expanded profile of the immune response elicited by metastatic tumor bearing Stat4−/− mice will provide additional insights regarding targets of the STAT4 signaling pathway which can be explored in the treatment of lymphatic metastasis in HNSCC.