FLT3 and leukemia: In addition, we tested the anti-proliferative ability of BPR1K871 in three other leukemia cell lines - U937 an AML-cell line which is FLT3 negative, RSV-11 cell line which is an ALL cell line with wt-FLT3 and in CML cell line K562 expressing Bcr-Abl fusion protein (Table 3).