Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

AML1 (RUNX1) encodes a DNA-binding subunit of the CBF transcription factor family and is required for the establishment of definitive hematopoiesis. AML1 is one of the most frequently mutated genes associated with human acute leukemia, suggesting that genetic alterations of the gene contribute to leukemogenesis. Here, we report the analysis of mice carrying conditional AML1 knockout alleles that were inactivated using the Cre/loxP system. AML1 was deleted in adult mice by inducing Cre activity to replicate AML1 deletions found in human MDS, familial platelet disorder and rare de novo human AML. At a latency of 2 months after induction, the thymus was reduced in size and frequently populated by immature double negative thymocytes, indicating defective T-lymphocyte maturation, resulting in lymphatic diseases with 50% penetrance, including atypical hyperplasia and thymic lymphoma. Metastatic lymphomas to the liver and the meninges were observed. Mice also developed splenomegaly with an expansion of the myeloid compartment. Increased Howell-Jolly body counts indicated splenic hypofunction. Thrombocytopenia occurred due to immaturity of mini-megakaryocytes in the bone marrow. Together with mild lymphocytopenia in the peripheral blood and increased fractions of immature cells in the bone marrow, AML1 deficient mice display features of a myelodysplastic syndrome, suggesting a preleukemic state.
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PMID:AML1 deletion in adult mice causes splenomegaly and lymphomas. 1624 65

If acute leukemia is the most frequent cancer in childhood (33%), it remains a very rare diagnosis in infants less than one year old, e.g. less than 5% of cases. At this age, the frequency of acute lymphoblastic leukemia (ALL) (almost all of B-lineage) is quite similar to the one of myeloblastic forms (AML). Infant leukemia frequently presents with high hyperleucocytosis, major tumoral burden and numerous extra-hematological features, especially in central nervous system and skin. Whatever the lineage, the leukemic cell is often very immature cytologically and immunologically. Rearrangements of the Mixed Lineage Leukemia (MLL) gene, located on band 11q23, are the hallmark of these immature leukemias and confer a particular resistance to conventional approaches, corticosteroids and chemotherapy. The immaturity of infants less than 1-year-old is associated to a decrease of the tolerable dose-intensity of some drugs (anthracyclines, alkylating agents) or asks questions about some procedures like radiotherapy or high dose conditioning regimen, responsible of inacceptable acute and late toxicities. The high level of severe infectious diseases and other high-grade side effects limits also the capacity to cure these infants. The survival of infants less than 1-year-old with AML is only 50% but similar to older children. On the other hand, survival of those with ALL is the same, then quite limited comparing the 80% survival in children over one year. Allogeneic stem cell transplantations are indicated in high-risk subgroups of infant ALL (age below 6 months, high hyperleucocytosis >300.10(9)/L, MLL-rearrangement, initial poor prednisone response). However, morbidity and mortality remain very important and these approaches cannot be extended to all cases. During the neonatal period, the dismal prognosis linked to the high number of primary failures or very early relapses and uncertainties about the late toxicities question physicians about ethics. It is an emergency to propose different strategies (targeted therapies) to these infants with acute leukemia as conventional trials failed to improve outcome.
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PMID:[Infant acute leukemia]. 2682 39

Mixed-phenotype acute leukemia is a rare form of leukemia that is associated with a poor prognosis. Most cases of mixed-phenotype acute leukemia are de novo. However, therapy-related mixed-phenotype acute leukemia can occur, and are often associated with exposure to topoisomerase-II inhibitors and alkylating agents. There are no known treatment guidelines for therapy-related mixed-phenotype acute leukemia. We present a patient with T/myeloid mixed-phenotype acute leukemia secondary to rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone R-CHOP chemotherapy for primary cutaneous diffuse large B-cell lymphoma. The patient's leukemic cells express CD34, an immaturity marker, CD3, a T-cell marker, and myeloperoxidase, a myeloid marker, and her history of chemotherapy for previous lymphoma supports the diagnosis of therapy-related T/myeloid mixed phenotype acute leukemia. Clinicians should be aware that this entity could be associated with R-CHOP chemotherapy. Given the complexity in diagnosis, and lack of treatment guidelines, a further understanding of the pathological and genetic principles of therapy-related mixed-phenotype acute leukemia will assist in future efforts to treat and categorize these patients. Mixed phenotype acute leukemia is a rare entity that accounts for two to five percent of all acute leukemias. Therapy- related mixed phenotype acute leukemia is an exceedingly rare hematological neoplasm that accounts for less than one percent of acute leukemias. We describe a case of therapy-related T/myeloid mixed phenotype acute leukemia following rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone R-CHOP chemotherapy for primary cutaneous diffuse large B-cell lymphoma DLBCL. The patient is a 63-year-old female who presented with several cutaneous nodules diagnosed as primary cutaneous DLBCL. The patient received R-CHOP chemotherapy and achieved remission. She remained in remission for four years until she presented with dyspnea, night sweats, weakness, and diffuse lymphadenopathy. Her presentation was initially concerning for recurrent lymphoma; however, a bone marrow biopsy and aspirate and a lymph node biopsy revealed a distinct blast population consistent with T/myeloid mixed phenotype acute leukemia T/M-MPAL. Given the patient's history of previous chemotherapy exposure, our patient represents a case of therapy-related T/myeloid mixed phenotype acute leukemia t-MPAL.
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PMID:THERAPY-RELATED T/MYELOID MIXED PHENOTYPE ACUTE LEUKEMIA IN A PATIENT TREATED WITH CHEMOTHERAPY FOR CUTANEOUS DIFFUSE LARGE B CELL LYMPHOMA. 2698 62


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