IRX1 and head and neck squamous cell carcinoma: IRX1, SLC5A8, FUSSEL18, EBF3, GBX2, HMX2, SEPT9 and ALX3 genes showed tumor suppressor activity in previous cancer studies (15–19) and were involved in transforming growth factor (TGF) signaling pathway which has a high frequency of alteration in HNSCC (15,20–23).