Lower Fas-associated phosphatase-1 expression predicted poor outcome in acute myeloid leukemia patients

Background Fas-associated phosphatase-1 (FAP-1) mediates tumor suppressor and tumor promoter effects through the inhibition of oncogenic tyrosine kinases and apoptosis, respectively. It was claimed responsible for the pathogenesis of some cancers; nevertheless, its role in acute myeloid leukemia (AML) is not clear. Patients and Methods FAP-1 expression was measured in 20 new AML patients and 12 apparently healthy individuals using real-time PCR. Results FAP-1 expression was significantly lower in AML patients compared with controls (P 0.001). Patients with relatively higher FAP-1 expression had significantly higher hemoglobin and platelets but lower white cell count (WCC) and lactic dehydrogenase (LDH) (P 0.001), thus reflecting lower tumor burden in this group. Patients’ response was assessed on day 28 after chemotherapy; we found that one of seven patients with FAP-1 expression up to 0.03945 achieved complete remission (CR) compared with eight of 13 patients with levels more than 0.03945. FAP-1 levels predicted the response in the subgroup with normal karyotype and in those with no FLT3-ITD as the majority of those with higher levels achieved CR (77.8 and 80%, respectively), whereas CR was seldom achieved in those with low levels. Conclusion Our data showed significantly reduced FAP-1 expression in AML patients. FAP-1 can be a useful tool in identifying patient’s risk in AML as the level of expression predicted the response.