Development and validation of flow cytometry methods for pharmacodynamic clinical biomarkers.

Flow cytometry is a powerful analytical tool for the analysis of multiple biological parameters of individual cells or particles within heterogeneous cell populations. It has been widely used in biomedical research to perform immunophenotyping, cell counting and numerous cell function assessments, such as intracellular cytokine production, protein phosphorylation, cell proliferation and apoptosis. The implementation of standardized flow cytometry-based biomarker assays in clinical trials remains a challenge due to the limited stability of clinical specimens and the technical variations between instruments. To ensure data quality, it is crucial to develop robust assays for clinical applications. In this review, we summarize current practice in developing, validating and implementing flow cytometry assays to evaluate biomarkers in clinical research.