A basket trial is a type of clinical trial that tests a single investigational drug or a combination of drugs across multiple cancer populations that have a shared genetic mutation, alteration, or biomarker. For example, the BRCA mutations have been linked to cancers in the breast, ovaries, prostate, pancreas, and possibly in the bile duct, esophagus and stomach. A drug that may be thought to target cancers caused in part by BRCA mutations might be tested in patients who have any of these cancers, even if the cancers are otherwise different from one another. Basket trials let researchers test the effectiveness of a specific therapeutic approach in multiple different cancers that may be driven by a common molecular cause.