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Background - The domain of precision oncology includes improving patient treatment outcomes based on the application of advanced molecular profiling methodologies to pathological specimens. To this end, optimal utilization of tumor tissue from diagnostic biopsies is an unmet medical need. This is especially relevant today since precision oncology is a rapidly evolving field where timely tumor genotyping is essential for the indication of many advanced and targeted therapies. National Comprehensive Cancer Network (NCCN) guidelines now mandate molecular testing for clinically actionable targets in certain malignancies. Patients diagnosed with advanced non-small cell lung cancer (NSCLC) are commonly of an older age and have significant co-morbidities. This frequently causes clinical dilemmas regarding the ability to obtain adequate amounts of tissue for tumor genotyping. In these cases, the tumor tissue may have been obtained by an image-guided biopsy, and the diagnosis of NSCLC proper determined via cytology. In certain instances, adequate tissue for tumor genotyping and/or a more advanced mutational analysis to identify oncogenic drivers may not be available. Methods - Formalin fixed paraffin embedded (FFPE) specimens were examined using advanced immuno-based laser capture microdissection (LCM), following a formal pathology review. In preparation for droplet digital PCR (ddPCR), DNA was extracted from samples and run with a series of positive and negative controls. Results - Utilizing lung cancer as an example, an improved genotyping approach for NSCLC solid tumors was developed and tested. The strategy involves optimization of the microdissection process and analysis of a large number of identical target cells from FFPE specimens sharing similar characteristics, in other words, single-cell subtype analysis. Immunostaining status, cell phenotype, and spatial location within a histological section are examples of shared characteristics that can guide cell procurement. Conclusions - Synergy between microdissection and ddPCR enhances molecular analysis. Demonstrated is a methodology that illustrates genotyping of a solid tumor from a small tissue biopsy sample in a time and cost-efficient manner, using immunohistochemistry directed LCM and ddPCR detection. Citation Format: Donald J. Johann, Ikjae Shin, Erich Peterson, Mathew Steliga, Jason Muesse, Katy Marino, Sarah Laun, Adam Roberge, Robert Weigman, Michael Emmert-Buck, Michael Tangrea. Advancing precision oncology by synergizing ddPCR with microdissection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 373.

e15083 Background: Improving patient treatment outcomes based on the application of advanced molecular profiling methodologies applied to pathological specimens is the purview of precision oncology. Optimal utilization of tumor tissue from diagnostic biopsies remains an unmet medical need. This is especially relevant today since precision oncology is a rapidly evolving field where timely tumor genotyping is essential for the indication of many advanced and targeted therapies. National Comprehensive Cancer Network (NCCN) guidelines now mandate molecular testing for clinically actionable targets in certain malignancies. Patients diagnosed with advanced non-small cell lung cancer (NSCLC) are commonly of an older age and have significant co-morbidities. Clinical dilemmas regarding the ability to obtain adequate amounts of tissue for tumor genotyping frequently occur. In these cases, the tumor tissue may have been obtained by an image-guided biopsy, and the diagnosis of NSCLC proper determined via cytology. Adequate tissue for tumor genotyping and/or a more advanced mutational analysis to identify oncogenic drivers may not be available, and the opportunity to explore more optimal therapy options (eg, TKI in lieu of chemotherapy) is lost. Methods: Following a formal pathology review formalin fixed paraffin embedded (FFPE) specimens were examined using advanced immuno-based laser capture microdissection (LCM). In preparation for droplet digital PCR (ddPCR), nucleic acids were extracted from samples and run with a series of positive and negative controls. Results: Utilizing lung cancer as an example, an improved genotyping approach for NSCLC solid tumors was developed and tested. The strategy involves optimization of the microdissection process and analysis of a large number of identical target cells from FFPE specimens sharing similar characteristics, in other words, single-cell subtype analysis. Immunostaining status, cell phenotype, and spatial location within a histological section are examples of shared characteristics that can guide cell procurement. Conclusions: With this approach, tumor molecular analysis is enhanced through the synergy between microdissection and ddPCR. Here we demonstrate a methodology that illustrates genotyping of a solid tumor from a small tissue biopsy sample in a time and cost-efficient manner, using immunohistochemistry-directed LCM along with the detection and absolute quantitation of mutations by ddPCR.

e15571 Background: Improving the utilization of tumor tissue from diagnostic biopsies is an unmet medical need. This is especially relevant today in the rapidly evolving precision oncology field where tumor genotyping is essential for the indication of many advanced and targeted therapies. National Comprehensive Cancer Network (NCCN) guidelines now mandate molecular testing for clinically actionable targets in certain malignancies. Patients diagnosed with advanced non-small cell lung cancer (NSCLC) are commonly of an older age and have significant co-morbidities. This frequently causes clinical dilemmas regarding the ability to obtain adequate amounts of tissue for tumor genotyping. In these cases, the tumor tissue may have been obtained by an image-guided biopsy, and the diagnosis of NSCLC proper determined via cytology. In certain instances, adequate tissue for tumor genotyping and/or a more advanced mutational analysis to identify oncogenic drivers may not be available. Methods: Following pathology review, formalin fixed paraffin embedded (FFPE) specimens were subjected to advanced immuno-based laser capture microdissection (LCM), DNA was extracted and prepped for droplet digital PCR (ddPCR) and run with a series of positive and negative controls. Results: Utilizing advanced stage lung cancer as an example, an improved genotyping approach for solid tumors is possible. The strategy involves optimization of the microdissection process and analysis of a large number of identical target cells from FFPE specimens sharing similar characteristics, in other words, single-cell subtype analysis. The shared characteristics can include immunostaining status, cell phenotype, and/or spatial location within a histological section. Conclusions: Synergy between microdissection and ddPCR enhances the molecular analysis. We demonstrate a methodology that illustrates genotyping of a solid tumor from a small tissue biopsy sample in a time and cost-efficient manner, using immunostain targeting as an example.