In the context of CMML and pre-CMML conditions, apart from a first evaluation of the BM blast percentage, aiming to exclude AML, and the evaluation of monocyte subsets, as was described earlier, neoplastic monocytes exhibit frequently an aberrant expression of CD56, CD2, CD5, CD10, CD23 or under-express CD13, CD14, CD15, CD33, CD38, CD45, and CD64 (133). The gene discussed is PTPRC; the disease is chronic myelomonocytic leukemia.