ULBP1 and acute myeloid leukemia: We treated with 2 mM metformin for 3 days 3 acute myeloid leukemia (AML) cell lines with different p53 status (OCI-AML3 cells express wt p53, HL60 are p53 null and NB4 express mutant (mut) p5320,29) and analyzed MICA/B and ULBP1 expression on plasma membrane.