CCND1 and breast cancer: Dysregulation of this pathway, through amplification or rearrangements of genes encoding D-, E-, A-, and B-cyclins (CCND1, CCND2, CCND3, CCNE1, CCNE2, CCNA1, CCNA2, CCNB1), CDK4, CDK6, CDK2, CDK1, and CDK7, has been documented in a vast number of cancers, including BC (26, 34, 35).