Constitutively activated mutants of the non-receptor tyrosine kinases (TK) ABL1 (Abelson murine leukemia viral (v-abl) homolog (1) protein) and JAK2 (JAnus Kinase 2 or Just Another Kinase 2) play a central role in the pathogenesis of clinically and morphologically distinct chronic myeloproliferative disorders but are also found in some cases of de novo acute leukemia and lymphoma.
JAK2V617F mutation was detected after transformation to CMML in 1 of them; in the other, a novel translocation t(5;12)(p13;q24) was observed at the time of progression to acute leukemia.
A translocation generating the constitutively activated fusion protein PCM1-JAK2 has also been recently found in atypical chronic myelogenous leukemia and acute leukemia.
ETV6-JAK2, PCM1-JAK2, BCR-JAK2) mutations have respectively been described in acute megakaryocytic leukemia and acute leukemia/chronic myeloid malignancies.
Thus, disruption of regulated p53 expression resulting in lack of detectable p53 mRNA even by RT-PCR occurs in about 30% of cases of AML; however, p53 alterations typical for human solid tumors are an infrequent event in most types of human acute leukemias.
Initial p53 mutation screening of blast cells from 29 patients with acute leukaemia by PCR-denaturing gradient gel electrophoresis showed that 2 had a silent codon 213 polymorphism and only the index case had a somatic mutation identified to be an 8 bp insertion in codon 281 (5'CCGGGGGG-3').
Overall, our data suggest that (1) TP53 inactivation is a relatively common event in leukemias with MLL rearrangements irrespective of the leukemic phenotype and of the patients' age; (2) at least two genetic lesions (i.e., MLL rearrangement and TP53 mutation) have accumulated in the short time (few weeks after the birth or conception of the child) corresponding to the development of acute leukemias of infancy.
A cohort of 75 MDS patients were investigated for RAS, FMS and p53 mutations, and these molecular findings were related to cytogenetics, clinical status, transformation to acute leukemia, prognostic scores and survival.
Immunohistochemical studies for GATA1 expression were performed on bone marrow biopsy specimens to define its role in the evaluation of acute leukemia and other hematologic disorders.
We did not find mutations in GATA1 in leukemic cells of DS patients with other types of acute leukemia, or in other patients with AMKL who did not have DS.
These mutations include JAK2, CALR and MPL mutations as the main disease drivers, mutations driving clonal expansion, and mutations that contribute to progression of chronic MPNs to myelodysplasia and acute leukemia.
These mutations include JAK2, CALR and MPL mutations as the main disease drivers, mutations driving clonal expansion, and mutations that contribute to progression of chronic MPNs to myelodysplasia and acute leukemia.
Recently, we and others found Wilms' tumour (WT1) gene expression to be increased in virtually all patients with acute leukaemias, whereas normal haemopoietic progenitors express the WT1 gene at much lower levels or not at all.