As more laboratories implement mechanisms to assess copy number aberrations across the genome in neoplastic disorders, a wealth of information has become available. In particular, greater clarity has been attained regarding the significance of certain copy number aberrations within specific tumor types, and paradigms for tumor classification and grading have been shifting to reflect the new findings. In this short discussion I will highlight some of these shifting paradigms and review how we in our lab have refined our approach to copy number data to match.