CD44 and head and neck neoplasm: Several humanized anti-CD44 and anti-CD44 variant monoclonal antibodies including bivatuzumab and RG7356 or RO5429083 were selected for non-invasive imaging of CD44 + tumors and tested in phase 1 clinical trials of breast cancer (NCT02254005), head and neck neoplasms (NCT02254018), and metastatic or locally advanced solid tumors (NCT01358903) [58].