CDK4 and neoplasm: CDK4 amplification (a CDK4/CEP12 ratio ≥2.0 or an average copy number of CDK4 signals/tumor cell nucleus ≥5.0 or percentage of tumor cells containing large clusters of CDK4 signal ≥10%) was found in 8.5% (44 of 520) of patients (Figures 1A,B), and other patients (91.5%, 476 of 520) showed non-amplification (low polysomy or disomy) (Figures 1C,D).