Difficult at times to distinguish from CMML, but granulocytic dysplasia is usually much more severe than in CMML. Nonspecific esterase staining of BM samples may be helpful in demonstrating the number of monocytes. Cytogenetics: clonal cytogenetic abnormalities in up to 80%; trisomy 8 and del(20q) are the most common, but abnormalities of chromosomes 13, 14, 17,19, and 12 are also commonly reported.⁴⁰  Molecular genetics: mutated NRAS, KRAS, or TET2 in nearly 30%³⁷ ; mutations of CBL, RUNX1, CEBPA, EZH2, or WT1 in 1%-10%^31,42,55 ; and JAK2 V617F occurs rarely if at all.⁴⁰