Eisai Co., Ltd., Epizyme, Inc. and Roche Holding AG announced a collaboration to develop an in vitro PCR (Polymerase Chain Reaction) based companion diagnostic test. The collaboration's goal is to identify lymphoma patients with non-wild type EZH2, including the Y641 mutation. Eisai and Epizyme are collaborating to develop an EZH2 inhibitor as a personalized therapeutic for patients with genetically defined cancers.