John is a leader in cancer research and molecular pathology, helping guide translational cancer research at Massachusetts General Hospital, where he also directed the Clinical Molecular Diagnostics Lab. He focuses on implementing biomarker screening technologies to monitor cancer and guide targeted therapies. His work on gene fusions like ALK, ROS1, and MET has advanced personalized lung cancer care. His lab developed “SNaPshot,” the first multiplexed tumor genotyping assay, and pioneered Anchored Multiplex PCR (AMP), now widely used and commercialized by ArcherDx. He continues to innovate, exploring spatial technologies and developing covalent inhibitors to target cancer drivers.