CXCR4 and head and neck cancer: Furthermore, we have also demonstrated that blocking CXCR4 with 1,1′ -[1,4-Phenylenebis(methylene)]bis-1,4,8,11-tetraazacyclotetradecane octahydrochloride (AMD3100), a CXCR4 antagonist, may be a potent anti-metastatic therapy for CXCR4-related head and neck cancer [5], [6].