Here, we stained PB samples from U‐CLL and M‐CLL patients for DNA content and Ki67 expression to distinguish cells in G0 (2n DNA, ki67lo), G1 (2n DNA, ki67hi), and S/G2/M (4n DNA, Ki67hi) phases (Figure 1A). The gene discussed is MKI67; the disease is B-cell chronic lymphocytic leukemia.