Polo‐like kinase 4 (PLK4) is the most structurally divergent member of the Polo protein family.90, 91, 92 Mice with a heterozygous mutation in Plk4 frequently develop tumors in the liver and other organs.93 The PLK4 protein is a key regulator of the centriolar duplication that is required for the precise reproduction of centrosomes during the cell cycle.94 A heterozygous Plk4 mutation (p.Ile242Asn) in mice caused patchy germ cell loss in the testes,95 similar to human Sertoli‐cell‐only syndrome (SCOS). This evidence concerns the gene PLK4 and small cell osteogenic sarcoma.