Analyzing large cancer populations could help both patients and providers better understand current prescribing and genetic testing practices for precision medicine.  In this study, we analyzed cancer patients, precision medicine drugs, and related genetic testing in the National Institutes of Health “All of Us” healthcare research database.  While cancer patients frequently received precision medicine drugs, the corresponding genetic tests which could improve the quality of care were rarely performed.  Our study highlights important gaps that must be addressed in order to realize the full potential of precision medicine. (By Drs. Jay G. Ronquillo and William T. Lester, https://jmg.bmj.com/content/early/2021/12/05/jmedgenet-2021-108112 )