Here, in order to better understand the results from spectral cytometry, it is important to mention that, since one of the main functions of Pax5 is maintaining non-B-cell genes repressed during B-cell differentiation, B-ALL tumors arising in Pax5+/− mice may mimic a Pax5−/− phenotype and express promiscuous surface lineage markers such as CD8, Mac1 or Gr1 (Figure 4B). Here, PAX5 is linked to precursor B-cell acute lymphoblastic leukemia.