Essential Thrombocythemia (ET)

Overview

Essential Thrombocythemia (ET) is a BCR-ABL1-negative myeloproliferative neoplasm characterized by sustained thrombocytosis and a high platelet count. It sits under MPN in OncoTree. JAK2 V617F is present in ~55% of ET cases; CALR exon 9 indels define the majority of JAK2/MPL-negative ET.

Cohorts in the corpus

Recurrent alterations

  • In 62 ET patients, JAK2 V617F was present in 35/62 (56%); CALR exon 9 frameshift indels were found in 70-84% of JAK2/MPL-negative ET cases (80/112 across full follow-up cohort). Median 6.5 somatic mutations per patient. CALR-mutated ET had significantly higher platelet counts (Wilcoxon P<0.001), lower hemoglobin (P=0.02), and higher risk of transformation to myelofibrosis (Fisher P=0.03) vs JAK2-mutated ET. PMID:24325359

Subtypes

  • No molecular subtypes formally defined beyond JAK2 vs CALR vs MPL driver status.

Therapeutic landscape

  • CALR mutation as a diagnostic and potential therapeutic target in JAK2/MPL-negative ET. PMID:24325359

Sources

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