Two types of MDS cell lines, MDS-L and SKM-1, were used in this in vitro test: MDS-L is a subline established from the human MDS cell line,16,17 and SKM-1 is a cell line established from an MDS/AML patient with no chromosomal abnormalities, but it has point mutations in NRAS and KRAS. The gene discussed is NRAS; the disease is acute myeloid leukemia.