CD19 and precursor B-cell acute lymphoblastic leukemia: Thus, in order to gain further insight into the molecular features of pediatric B-ALL in this group and considering that most of the gene expression profiles of B-ALL have been conducted using mononuclear cells (lymphocytes B and T and monocytes) from patient samples, we performed a global gene expression analysis of a sample of flow-sorted CD10 + /CD19 + precursor B (pre-B) lymphoblasts from peripheral blood (PB) or bone marrow (BM) samples of B-ALL patients, to prevent contamination with other mononuclear or non-leukemic cells.