Precision medicine is an emerging field in medicine for disease prevention and treatment that takes into account the individual variability in genes, environment, and lifestyle for each individual patient. The authors have developed a special program as part of the Englander Institute for Precision Medicine to grow patient-derived, 3-dimensional tumor organoids for tumor-specific drug testing, tailoring treatment strategies, and as models for studying drug resistance. Routine cytology preparations represent a cost-effective and powerful tool to aid in performing molecular testing in the age of personalized medicine. In this commentary, the platforms used for the characterization and validation of patient-derived, 3-dimensional tumor organoids are outlined and discussed, and the role of cytology as a cost-effective and powerful quality-control measure is illustrated. Cancer Cytopathol 2016;124:167-173. © 2015 American Cancer Society.