This term the Supreme Court and the Federal Circuit under its en banc authority have had before them cases involving fundamental issues in intellectual property law, including the patentability of diagnostic processes, the standard for proving inequitable conduct and the applicability of intervening rights to reexamination proceedings. Anthony Lo Cicero of Amster, Rothstein & Ebenstein LLP discusses the cases of Mayo Collaborative Services v. Prometheus Laboratories, Inc., Association for Molecular Pathology v. Myriad Genetics, et al., Therasence, Inc. v. Becton, Dickinson and Co., and Marine Polymer Technologies, Inc. v. Hemcon, Inc., and the likely impact of each on IP practitioners and companies.