Changes

==Common Alteration Types==

==Common Alteration Types==

Bi-allelic CEBPA mutations define a specific entity in the 2016 WHO classification of hematologic neoplasms [1]. AML cases with only one CEBPA mutation have different biologic and clinical characteristics and should not be classified into this category.  

* Bi-allelic ''CEBPA'' mutations define a specific entity in the 2016 WHO classification of hematologic neoplasms [1]. AML cases with only one ''CEBPA'' mutation have different biologic and clinical characteristics and should not be classified into this category.  

AML with bi-allelic CEBPA mutations typically presents 'de novo'; it accounts for approximately 4-9% of AML cases in children and young adults, and appears to be less common in older patients.  

 

Morphologically it meets the criteria for AML with or without maturation and more rarely may show myelomonocitic or monoblastic features. There are no any distinctive morphologic or immunophenotypic characteristics.  

* AML with bi-allelic ''CEBPA'' mutations typically presents ''de novo''; it accounts for approximately 4-9% of AML cases in children and young adults, and appears to be less common in older patients.  

More than 70% of the cases have a normal karyotype. The remaining cases may show del(9q) or different non-specific chromosome abnormalities.  

 

The bi-allelic CEBPA mutation is associated with a specific gene expression profile in leukemia clones, that is not seen in cases with a single CEBPA mutation. FLT3-ITD mutation is observed in 5-9% of the cases, while GATA2 zing-finger 1 mutation occurs in 39% of the patients. Importantly, all patients with bi-allelic CEBPA mutations have to be evaluted for the germline mutation status, to exclude germline inheritance of one of the alleles. Germline mutations in one copy of the CEBPA gene are associated with a familial AML syndrome which typically manifests as development of leukemia in childhood or adolescence (median age 24.5 years) in the absence of preceding abnormal blood counts or other clinical phenotypes. In AML with germline CEBPA mutation, the first mutation is germline and commonly occurs in the 5' end of the gene. The second mutation occurs as a somatic change in leukemia cells and typically localizes within the 3' end of the gene. The disorder appears to have near-complete penetrance for development of AML. AML with germline CEBPA mutation is associated with a favorable prognosis, with the survival rate reported in one study as 67% [2]. However, patients frequently experience recurrence, which at least in a subset of cases may in fact represent development of a novel independent clone with bi-allelic mutation rather than a true relapse.  

* Morphologically it meets the criteria for AML with or without maturation and more rarely may show myelomonocitic or monoblastic features. There are no any distinctive morphologic or immunophenotypic characteristics.  

Sporadic cases of AML with bi-allelic CEBPA mutations are also associated with a favorable prognosis, similar to that of inv(16) or t(8;21) AML. The influence of FLT3-ITD and GATA2 mutations on prognosis of AML with bi-allelic CEBPA mutations is presently unclear.  

 

* More than 70% of the cases have a normal karyotype. The remaining cases may show del(9q) or different non-specific chromosome abnormalities.  

 

* The bi-allelic ''CEBPA'' mutation is associated with a specific gene expression profile in leukemia clones, that is not seen in cases with a single ''CEBPA'' mutation. ''FLT3''-ITD mutation is observed in 5-9% of the cases, while ''GATA2'' zing-finger 1 mutation occurs in 39% of the patients. Importantly, all patients with bi-allelic ''CEBPA'' mutations have to be evaluted for the germline mutation status, to exclude germline inheritance of one of the alleles. Germline mutations in one copy of the ''CEBPA'' gene are associated with a familial AML syndrome which typically manifests as development of leukemia in childhood or adolescence (median age 24.5 years) in the absence of preceding abnormal blood counts or other clinical phenotypes. In AML with germline ''CEBPA'' mutation, the first mutation is germline and commonly occurs in the 5' end of the gene. The second mutation occurs as a somatic change in leukemia cells and typically localizes within the 3' end of the gene. The disorder appears to have near-complete penetrance for development of AML. AML with germline ''CEBPA'' mutation is associated with a favorable prognosis, with the survival rate reported in one study as 67% [2]. However, patients frequently experience recurrence, which at least in a subset of cases may in fact represent development of a novel independent clone with bi-allelic mutation rather than a true relapse.  

Sporadic cases of AML with bi-allelic ''CEBPA'' mutations are also associated with a favorable prognosis, similar to that of inv(16) or t(8;21) AML. The influence of ''FLT3''-ITD and ''GATA2'' mutations on prognosis of AML with bi-allelic ''CEBPA'' mutations is presently unclear.  

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