BACKGROUND The mixed lineage leukemia(MLL)-eleven-nineteen lysine-rich leukemia(ELL)fusion gene is a rare occurrence among the various MLL fusion genes.We present the first case in which myeloid sarcoma(MS)was the onl...BACKGROUND The mixed lineage leukemia(MLL)-eleven-nineteen lysine-rich leukemia(ELL)fusion gene is a rare occurrence among the various MLL fusion genes.We present the first case in which myeloid sarcoma(MS)was the only manifestation of adult MLL-ELL-positive acute myeloid leukemia(AML).CASE SUMMARY We report a case of a 33-year-old male patient who was admitted in June 2022 with a right occipital area mass measuring approximately 7 cm×8 cm.Blood work was normal.The patient underwent right occipital giant subscalp mass excision and incisional flap grafting.Immunohistochemistry was positive for myeloperoxidase,CD43 and CD45 and negative for CD3,CD20,CD34,and CD56.The bone marrow aspirate showed hypercellularity with 20%myeloblasts.Flow cytometry showed that myeloblasts accounted for 27.21%of the nucleated cells,which expressed CD33,CD38,and CD117.The karyotype was 46,XY,t(11,19)(q23;p13.1),-12,+mar/46,XY.Next-generation sequencing showed a fusion of MLL exon 7 to exon 2 of ELL.A diagnosis of MLL-ELL-positive AML(M2 subtype)with subcutaneous MS was made.CONCLUSION MLL-ELL-positive AML with MS is a rare clinical entity.Additional research is needed to elucidate the molecular mechanisms of the pathogenesis of MS.展开更多
Mixed lineage leukemia(MLL)is an aggressive and refractory blood cancer that predominantly occurs in pediatric patients and is often associated with poor prognosis and dismal outcomes.Thus far,no effective target ther...Mixed lineage leukemia(MLL)is an aggressive and refractory blood cancer that predominantly occurs in pediatric patients and is often associated with poor prognosis and dismal outcomes.Thus far,no effective target therapy for the treatment of MLL leukemia is available.MLL leukemia is caused by the rearrangement of MLL genes at 11q23,which generates various MLL chimeric proteins that promote leukemogenesis through transcriptional misregulation of MLL target genes.Biochemical studies on MLL chimeras have identified that the most common partners exist in the superelongation complex(SEC)and DOT1L complex,which activate or sustain MLL target gene expression through processive transcription elongation.The results of these studies indicate a transcription-related mechanism for MLL leukemogenesis and maintenance.In this study,we first review the history of MLL leukemia and its related clinical features.Then,we discuss the biological functions of MLL and MLL chimeras,significant cooperating events,and transcriptional addiction mechanisms in MLL leukemia with an emphasis on potential and rational therapy development.Collectively,we believe that targeting the transcriptional addiction mediated by SEC and the DOT1L complex will provide new avenues for target therapies in MLL leukemia and serve as a novel paradigm for targeting transcriptional addiction in other cancers.展开更多
基金Supported by Scientific Research Project of Anhui Provincial Health Commission,No.AHWJ2021b005.
文摘BACKGROUND The mixed lineage leukemia(MLL)-eleven-nineteen lysine-rich leukemia(ELL)fusion gene is a rare occurrence among the various MLL fusion genes.We present the first case in which myeloid sarcoma(MS)was the only manifestation of adult MLL-ELL-positive acute myeloid leukemia(AML).CASE SUMMARY We report a case of a 33-year-old male patient who was admitted in June 2022 with a right occipital area mass measuring approximately 7 cm×8 cm.Blood work was normal.The patient underwent right occipital giant subscalp mass excision and incisional flap grafting.Immunohistochemistry was positive for myeloperoxidase,CD43 and CD45 and negative for CD3,CD20,CD34,and CD56.The bone marrow aspirate showed hypercellularity with 20%myeloblasts.Flow cytometry showed that myeloblasts accounted for 27.21%of the nucleated cells,which expressed CD33,CD38,and CD117.The karyotype was 46,XY,t(11,19)(q23;p13.1),-12,+mar/46,XY.Next-generation sequencing showed a fusion of MLL exon 7 to exon 2 of ELL.A diagnosis of MLL-ELL-positive AML(M2 subtype)with subcutaneous MS was made.CONCLUSION MLL-ELL-positive AML with MS is a rare clinical entity.Additional research is needed to elucidate the molecular mechanisms of the pathogenesis of MS.
基金supported by grant from the“Thousand Young Talent Program”awarded to K.L.
文摘Mixed lineage leukemia(MLL)is an aggressive and refractory blood cancer that predominantly occurs in pediatric patients and is often associated with poor prognosis and dismal outcomes.Thus far,no effective target therapy for the treatment of MLL leukemia is available.MLL leukemia is caused by the rearrangement of MLL genes at 11q23,which generates various MLL chimeric proteins that promote leukemogenesis through transcriptional misregulation of MLL target genes.Biochemical studies on MLL chimeras have identified that the most common partners exist in the superelongation complex(SEC)and DOT1L complex,which activate or sustain MLL target gene expression through processive transcription elongation.The results of these studies indicate a transcription-related mechanism for MLL leukemogenesis and maintenance.In this study,we first review the history of MLL leukemia and its related clinical features.Then,we discuss the biological functions of MLL and MLL chimeras,significant cooperating events,and transcriptional addiction mechanisms in MLL leukemia with an emphasis on potential and rational therapy development.Collectively,we believe that targeting the transcriptional addiction mediated by SEC and the DOT1L complex will provide new avenues for target therapies in MLL leukemia and serve as a novel paradigm for targeting transcriptional addiction in other cancers.
