Additional Study Information: Participants are being invited to take part in a clinical research study because they have been diagnosed with locally advanced or metastatic solid tumors with mutations in the following genes: MRE11, RAD50, NBN, or CCNE1 amplification. If the participant takes part in the study, they will take an investigational drug referred to as ZN-c3 (Study Drug). Investigational means that the Study Drug is currently being tested and has not been approved by the U.S. Food and Drug Administration (FDA) or any other health or regulatory authority in other countries. The purpose of this study includes the following: to test the efficacy and safety of the Study Drug, ZN-C3, and to find out what effects, good and/or bad, it has on you and your cancer. To understand how the body absorbs and processes the Study Drug, ZN-C3 by measuring the amount of the Study Drug, ZN-C3 in the blood before, during, and after receiving the Study Drug, ZN-C3. (This is called pharmacokinetics (PK) testing)