Principal Scientist I - Molecular Histology Scientist

Job Description Summary #LI-Onsite Internal Title: Principal Scientist I Location: Cambridge, MA We are seeking a highly motivated and scientifically driven Principal Scientist I to join the Molecular Histology Laboratory within Preclinical Safety and Investigative Pathology. This position will serve as a technical subject matter expert responsible for developing, optimizing, and implementing advanced tissue-based assays that support preclinical toxicology, investigative pathology, translational research, and drug development programs. The successful candidate will possess deep expertise in molecular localization technologies, digital pathology, and tissue-based biomarker assessment. This individual will provide hands-on laboratory leadership in assay development and execution while collaborating closely with pathologists, laboratory scientists, and multidisciplinary project teams. This role requires extensive experience with immunohistochemistry (IHC), multiplex IHC, in situ hybridization (ISH/RNAscope), automated staining platforms, digital pathology workflows, and image analysis technologies.   Job Description Key Responsibilities Molecular Localization and Assay Development • Develop, optimize, validate, and implement tissue-based assays, including immunohistochemistry (IHC), multiplex immunofluorescence, and in situ hybridization (ISH/RNAscope). • Serve as a molecular histology subject matter expert by evaluating antibodies, probes, controls, and assay strategies to generate robust, reproducible, and scientifically meaningful data. • Operate, maintain, and optimize automated staining platforms, including Ventana ULTRA and Leica BOND systems, while developing automated workflows for IHC and ISH assays. • Troubleshoot complex technical challenges and establish best practices for assay performance and quality control. • Establish standardized protocols, acceptance criteria, troubleshooting guides, and assay performance metrics. • Utilize digital pathology workflows, including whole-slide imaging, image analysis, and data management using LIMS and electronic laboratory notebook (eLN) platforms. • Maintain accurate, contemporaneous, and traceable experimental records in approved electronic systems. • Partner with pathologists and multidisciplinary project teams to support objectives with clear communication.  Prepare clear study summaries, technical reports, presentations, and recommendations for project teams. • Contribute to continuous improvement and implementation of emerging technologies that enhance laboratory capabilities and scientific impact. • Ensure compliance with laboratory safety, quality, documentation, and data integrity standards while maintaining sample traceability and study records.   Essential Requirements • Bachelors or Master’s Degree required in Biological Sciences, Pathology, Molecular Biology, Cell Biology, Immunology, or related scientific discipline with 8+ years directly relevant laboratory experience. • Extensive hands-on experience with molecular localization techniques including: • • Immunohistochemistry (IHC) • Multiplex IHC/Immunofluorescence • In Situ Hybridization (ISH) • RNAscope and related RNA detection technologies • Proven expertise in development, optimization, validation, and troubleshooting of tissue-based assays. • Strong experience with automated staining platforms including Ventana ULTRA and/or Leica BOND systems. • Working knowledge of histology workflows, tissue processing, fixation methods, and sample preparation techniques. • Experience with whole-slide imaging systems, digital pathology platforms, and image analysis tools. • Excellent attention to detail and commitment to data quality and scientific rigor. • Strong written, verbal, and presentation communi