Among molecular subgroups, a higher concentration of S100A8 in bone marrow plasma was observed in AML with FLT3-ITD mutation, in NPM1 muted AML or with a tendency in inv(16) (p13.1q22).However, intracellular measurement of S100A8, by flow cytometry highlighted that it mainly originated from both monocytes and leukemic cells expressing monocytic markers such as promonocytes and monoblast, arguing for the role of bone marrow microenvironment in secretion of S100 proteins. The gene discussed is NPM1; the disease is acute myeloid leukemia.