I. Clinical and hematologic features (all 4 features mandatory) |
- Peripheral blood monocyte count ≥1 × 109/L
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- Blast percentage in peripheral blood and bone marrow <20%
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- Absence of Philadelphia chromosome (BCR/ABL1 rearrangement)
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II. Genetic studies (1 finding sufficient) |
- Somatic mutation in PTPN11* or KRAS* or NRAS*
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- Clinical diagnosis of NF1 or NF1 mutation
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- Germ line CBL mutation and loss of heterozygosity of CBL¶
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III. For patients without genetic features, besides the clinical and hematologic features listed under I, the following criteria must be fulfilled: |
- Monosomy 7 or any other chromosomal abnormality or at least 2 of the following criteria:
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- Hemoglobin F increased for age
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- Myeloid or erythroid precursors on peripheral blood smear
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- GM-CSF hypersensitivity in colony assay
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- Hyperphosphorylation of STAT5
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