CD33 and cancer: Therefore, we tested whether soluble MICA (shed from the cell surface by proteolytic cleavage, found at levels up to 1–50 ng/mL in the sera of patients with cancer including AML [41,42,43,44], and representing a dominant soluble NKG2D ligand in AML patients [43,44]) and/or CD33 could interfere with CC-96191 cytotoxicity.