acml is a rare myeloproliferative neoplasm with a combination of myeloproliferation and dysplastic hematopoiesis in clinical manifestation . some recent studies have increased our understanding of the genetic drivers of mpn 17 , more recently , substantial progress has been discovered in the understanding of the pathogenic gene mutations driving acml , such as setbp1 813 , csf3r 13 . . here , we report a rare case of acml in a patient after chemotherapy for m4 . herein , we discussed the potential impact of the finding on the pathogenic gene of these disorders . a 63-year - old man was referred to our hospital because of increases in blood cell counts . laboratory tests showed a hemoglobin level of 7.2  g / dl , leukocytes 28    10/l , and platelets 76    10/l . there was no splenomegaly , hepatomegaly , lymphadenopathy , or obvious morphological abnormalities of hemocyte ( include bone marrow and peripheral blood ) were found . examination of the bone marrow shows a significant myeloid hyperplasia with full myeloblasts ( 35% in the peripheral blood ) , pox ( strongly positive ) , nse ( 100% positive ) , and restrain by naf . chromosome analysis with g - banded karyotype of the unstimulated bone marrow cells showed 46 , xy , in all 24 metaphase spreads . the patient was diagnosed with acute myelocytic leukemia ( aml - m4 , fig.1 ) . the patient was treated with cag ( acr , ara - c , g - csf , more than 60  years of age and low doses of chemotherapy regimens ) chemotherapy regimens , at this dose , a hematological complete remission ( cr ) after each chemotherapy was attained , after 6 cag chemotherapy regimens , after the last stage of chemotherapy ( remain complete remission , wbc count was normal ) , separately . about 3  months later , peripheral blood count revealed a workup for leukocytosis ( 16.4    10/l ) and thrombocytosis ( 378    10/l ) . examination of peripheral blood smear revealed blast cells ( 3.5% ) , immature granulocytes ( 16% ) , and the phenomenon of dysplasia in granulopoiesis . neither monocytosis ( 2% ) , basophilia ( 1% ) , nor eosinophilia ( 0.5% ) was seen . the neutrophil alkaline phosphatase ( nap ) score was 3 ( control , 78 ) . bone marrow biopsy was observed with an obvious myeloid proliferation ( include mature neutrophils and neutrophil precursors ) , granulocytic dysplasia , and marked megakaryocytosis ( include some small megakaryocytes ) ( fig.1 ) . the case of acml and 43 additional cases of aml ( m4 ) were confirmed to meet who-2008 14 diagnostic criteria . the analysis of the gene mutational status (  ) : no mutation was detected ; ( + ) : the presence of a mutation . frequency of setbp1 mutations in m4 patients the result of cytomorphology and cytochemistry in m4 and acml samples . cytochemistry was performed for myeloperoxidase(mpo ) , neutrophil alkaline phosphatase ( nap ) , and nonspecific esterase ( nse+naf ) , bone marrow biopsy underwent h&e staining . setbp1 mutation of paired acml ( bone marrow ) and  normal ' dna from a case with m4 was detected by sanger sequencing . setbp1 mutation ( showed a heterozygous mutation a / c ) was located in the part of the gene encoding the ski homologous ( aa 706917 ) domain ( fig.2 ) . setbp1-mutant showed significantly higher setbp1 mrna expression levels compared to wild - type case without setbp1 overexpression . schematic overview of setbp1 protein structure and a novel mutation of setbp1 gene in acml . the mutation located in the ski - homologous region of setbp1 , vertical arrows indicate affected nucleotide , suggested the presence of heterozygous mutation ( encoding a p.asp868ala alteration ) . recently , substantial progress has been found for the understanding of the pathogenic gene mutations driving acml , such as cbl 57 , ras 8 , pdgfrb 4 , setbp1 813 , tet2 57 , and csf3r 13 . so far , setbp1 has been identified the most specific genetic mutation in the acml 8,9 . in an aml1/eto - positive patient , a potential mechanism regulating the evolution from m4 to secondary acml with mutation of setbp1 will be discussed . insights into the evolution of a case from m4 to acml , clinical samples available to successfully analyze were collected serially at different stages of clinical time points . we performed exon sequencing and identified a new mutation in setbp1 ( encoding a p.asp868ala alteration ) , which was subsequently confirmed by sanger sequencing . no setbp1 mutation was found in 43 aml samples , indicated that there was a low frequency of setbp1 mutation in aml . furthermore , previous studies demonstrated that setbp1 is mutated at lower frequencies in other mds / mpn 9 . the same and closely neighboring setbp1 mutations encoding changes in have been reported , such as e858k in acml 8,9 , d868a in sgmfs 10 , d868g / y 9,11 , and s869r 9 in myeloid malignancies , d868n in sgmfs 10 , acml 8,9,12 , jmml 13 and mds 12 , s869n in mds 12 , and myeloid malignancies 11 , all mutations clustered in the ski homologous region of setbp1 are within a stretch of 22 aa ( aa 858880 ) . but so far no setbp1 ( d868a ) mutation has been identified in acml patient . setbp1 when phosphorylated , the ski homologous region will be bound by the -trcp1 and thus leads to the degradation 8 . however , the setbp1 mutants disrupt this progression and lead to the increased setbp1 and set expression , which lower pp2a activity and show significantly more efficient colony formation and faster proliferation of cells 8 . in addition , previous studies have confirmed that mutant setbp1 immortalized myeloid leukemia cell 18 , our finding is consistent with the gain of leukemogenic function due to setbp1 mutation . in agreement with these findings , the p.asp868ala alteration abrogated a site for degradation , and cells expressing this mutant exhibited higher amounts of setbp1 mrna relative to the expressing the aml - m4 cr setbp1 mrna . we also propose that mutation could increase protein stability , resulting in greater protein amounts ( similar to overexpression of setbp1 mrna ) 8 . these cause the gain of function associated with myeloid leukemic transformation and may be relevant to the pathogenesis of acml . these observations indicated an association of wt-1 mutated 19 with setbp1 mutated cases in acml patients . this signifies a potential influence of the other oncogene genes on pathogenesis of acml . whereas jak2v617f - negative mpn may be observed with mplw515 20,21 , fip1l1-pdgfr 
 22 , etv6-pdgfr 
 4 mutations , and they are all negative in our sample . none of the m4 had setbp1 mutation at the time of initial stage , clearly revealed that setbp1 mutation was acquired with the leukemic evolution . we propose that setbp1 may be a high risk for leukemic evolution . additional screening for setbp1 mutations might be helpful for the diagnosis of acml , even though this particular observation requires further confirmation in a larger cohort of who - defined acml . otherwise , what indicates that acml does not precede the aml occurrence ? though equally likely , the patient might have had undiagnosed setbp1 causing acml that was transiently out - competed by a runxi - runx1t1 aml clone . at cr , chemotherapy eradicated the aml1-eto clone , leaving the setbp1 clone detectable again . there are now many examples of aml that develop on a background of myeloproliferative neoplasm  for example , jak2 v617f mutation  without detection of the mutation in aml blast cells , suggesting that the aml develops from a distinct stem cell or progenitor , possibly on a background of other mutations ( such as tet2 mutation ) 23,24 . in conclusion , we identified a new mutation in setbp1 ( encoding a p.asp868ala alteration ) of the acml , setbp1 mutation may be acquired during leukemic evolution . the authors declare that the paper is the authors ' original work , has not been submitted to or published by another journal , and there are no competing financial interests or conflicts of interest in association with this research .
key clinical messageto investigate an oncogenic mutation of setbp1 in the evolution from acute myelomonocytic leukemia ( m4 ) to secondary acml . 
 clinical data and molecular studies were analyzed of paired acml and ' normal'dna from a case with m4 . 
 we identified a mutation in setbp1 ( encoding a p.asp868ala alteration ) . 
 the analysis of paired sample indicated that setbp1 mutation was acquired during leukemic evolution .