PLK4 and precursor B-cell acute lymphoblastic leukemia: Non-plasma cell controls comprised 205 completely pictured centrioles in 136 CD138neg bone marrow mononuclear cells from 3 healthy donors, 380 centrioles in 262 leukemic B-cells from 2 patients with B-CLL and 6 patients with B-ALL, and 137 centrioles in 53 U2OS cells conditionally over-expressing PLK4, the principal kinase regulating centriole duplication [2–4, 10].