Using Siglec-5 as a biomarker to detect low levels of AML cells in human bone marrow specimen. A representative AML bone marrow (left panels in a. and b.) and normal bone marrow (NOR BM) (right panels in a. and b.) case are shown. In addition, the AML specimen is diluted with normal bone marrow cells (middle panels in a. and b.), and the final AML cell fraction was approximately 1.6%. CD34(+) cells in three samples are gated selectively according to the levels of CD34 and SSC (a.), and the expression of Siglec-5 on CD34(+) cells is displayed in (b.) The CD34(+) leukemic cells (red dots in b.) have higher levels of Siglec-5 than normal CD34(+) cells in normal bone marrow (blue dots in b).