Figure 4 shows that only about 25% of the blasts were responsive. The correlation study performed using blasts isolated from AML patients indicated that blasts carrying FLT3 mutations are resistant to 1,25D and to its analogs [73]. Surprisingly, available cell lines which carry FLT3 mutations, MV-11 and MOLM-13, are responsive in vitro to 1,25D and to analogs [74]. The gene discussed is FLT3; the disease is acute myeloid leukemia.