Thirty OM-CMMLs (>10% monocytes in BM and >10% PB monocytes with absolute monocyte count of 0.5-1x10 9 /L) and 20 overt CMMLs (11 CMML0, 6 CMML1, 3 CMML2/AML) were compared, of which 21/30 and 20/20 cases were subjected to 21-or 45-gene mutation analysis.