Unique frameshift mutations in the calreticulin (CALR) gene, which encodes an endoplasmic reticulum (ER)-localized molecular chaperone, have been identified in patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF), which are subgroups of myeloproliferative neoplasms (MPNs).
"Driver" mutations in JAK2, MPL and indels in CALR underlie the vast majority of cases of PMF and post-ET MF; the remainder (≈ 10%) lack identifiable driver mutations, but other clonal markers are usually detectable.
Frameshifting mutations (-1/+2) of the calreticulin (CALR) gene are responsible for the development of essential thrombocythemia (ET) and primary myelofibrosis (PMF).
Effect of CALR and JAK2 mutations on the clinical and hematological phenotypes of the disease in patients with myelofibrosis - long-term experience from a single center.
AML transformation occurred faster in SMF than in PMF and patients who transformed to AML were more SRSF2-mutated and less CALR-mutated at MF sampling.
Calreticulin (CALR) exon 9 frameshift mutations have recently been identified in 30-40% of patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF) without JAK2 or MPL mutations.
Mutation loads of the CALR mutations were between 13% and 94% with mean value in PMF cases significantly higher than ET cases (49.94 vs 41.09; t-test, p=0.004).
Along with these results, a second review of bone marrow histology, flowcytometry and the detection of a calreticulin gene (<i>CALR</i>) mutation helped with the correct diagnosis of PMF.
One hundred five Philadelphia-negative MPN patients, including polycythemia vera (PV), essential thrombocythaemia (ET), and primary myelofibrosis (PMF) were initially screened for JAK2 mutations by amplification-refractory mutation system (ARMS-PCR) methodology and were further subjected to detection of CALR gene mutations by our in-house assay, a PCR based amplicon length differentiation assay (PCR-ALDA).
Finally, we tested the combined effect of busulfan and veliparib on CD34<sup>+</sup> cells obtained from the bone marrow or peripheral blood of 5 patients with JAK2<sup>V617F</sup>-mutated and 2 patients with CALR-mutated MF.
ABSTRACT: Background The BCR-ABL-negative myeloproliferative neoplasms, i.e., polycythemia vera, essential thrombocythemia (ET), and myelofibrosis (MF), are characterized by mutations in JAK2, CALR, or MPL.
Notably, mutations in chromatin regulators ASXL1 and/or EZH2 were identified as the first genetic lesions, preceding both JAK2-V617F and CALR mutations, and are thus drivers of clonal myelopoiesis in a PMF subset.
Mutations of JAK2V617F, JAK2 exon 12, MPL W515L/K and CALR were analysed in 439 Argentinean patients with BCR-ABL1-negative MPN, including 176 polycythemia vera (PV), 214 essential thrombocythemia (ET) and 49 primary myelofibrosis (PMF).
In this study, we generated an induced Pluripotent Stem (iPS) cell line derived from a 65-year old male PMF patient carrying the 5-pb insertion in the CALR gene (CALR<sup>ins5</sup>) and the c.437 G > A mutation in the TP53 gene (p.W146X).
Polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) are classical myeloproliferative neoplasms (MPN), characterized by specific somatic mutations in JAK2, CALR or MPL genes.