The overexpression of a family of antiapoptotic proteins termed inhibitor of apoptosis (IAP) proteins, including cellular IAP 1 and 2 (cIAP1 and cIAP2, encoded by BIRC2 and BIRC3), X-chromosome-linked IAP (XIAP, encoded by BIRC4), and survivin was reported to confer resistance to radiation therapy and chemotherapy and cause poor prognoses of patients with head and neck cancers, including OSCC [4,5,6,7]. Here, XIAP is linked to head and neck cancer.