Thus, PCA revealed that: i) CD45 and CD56 were the most informative backbone markers for distinction between CD45− non-hematopoietic tumor cells and CD45+ normal cells, whereas ii) CD19, cyCD3, and smCD3 in combination with CD45 were critical to distinguish between leukemia/lymphoma cells and non-hematopoietic tumor cells (Figure 2). This evidence concerns the gene CD19 and leukemia.