HAT‐L4 mRNA levels appeared similar in bone marrow cells from various AML FAB classes, including FAB M3 that is more typical for acute promyelocytic leukemia cells and behaves differently from the cells of the other FAB classes (Figure 1E).32 Western blotting confirmed high HAT‐L4 protein levels in AML bone marrow cells compared with those in CML, ALL and CLL bone marrow cells (Figure 1F,G). The gene discussed is TMPRSS11F; the disease is acute promyelocytic leukemia.