Table 2.

Diagnostic criteria of JMML

I. Clinical and hematologic features (all 4 features mandatory)

Peripheral blood monocyte count > 1 × 109/L

Blast percentage in peripheral blood and bone marrow <20%

Splenomegaly (not always apparent at diagnosis)

Absence of Philadelphia chromosome (BCR/ABL rearrangement)

II. Oncogenetic studies (1 finding is sufficient)

Somatic mutation in PTPN11, KRAS, or NRAS

Clinical diagnosis of NF1 or germ line NF1 mutation

Germ line CBL mutation and loss of heterozygosity of CBL

III. For patients with the clinical and hematologic features under (I) but without an oncogenetic criterion (10%), at least 2 of the following criteria must be fulfilled:

Monosomy 7 or any other chromosomal abnormality

HbF increased for age

Myeloid precursors in peripheral blood

Spontaneous growth or granulocyte-macrophage colony-stimulating factor hypersensitivity in colony assay

Hyperphosphorylation of STAT5