Among the 425 patients with the information on the CDK4/6i treatment before biopsies collection and the CDK4 amplification status, 69 have been tested (when RNA was available) for CDK4 expression by a real-time quantitative RT-PCR: 3 CDK4-amplified tumours and 66 CDK4-unamplifified tumours. This evidence concerns the gene CDK4 and neoplasm.