Additional Study Information: The purpose of this research study is to test the safety of an investigational drug, PRT3789, at different dose levels to find out what effects, good and/or bad, PRT3789 has on Advanced or Metastatic Solid Tumors with a SMARCA4 Mutation. Mutations are changes or alterations in the DNA (genetic material) of your cells. A SMARCA4 mutation has been linked to certain cancers. Investigational means that the study drug is currently being tested and has not been approved for use by any health authority such as the United States (US) Food and Drug Administration (FDA) or any other health or regulatory authority in other countries for the treatment of cancer. The study drug, PRT3789, is a SMARCA2 degrader meaning that it may help break down the protein called SMARCA2. This protein is part of a cell life cycle that allows tumor cells to grow and spread. When SMARCA2 breaks down, it causes tumor cells to stop progressing through their life cycle and die. Studies done in animals have shown that PRT3789 can help break down this protein and induce cancer cell death, but PRT3789 has not yet been tested in humans. Cancer include: bladder cancer, breast cancer, colon and rectal cancer, esophageal cancer, gynecologic cancers, head and neck/oral cancer, kidney cancer, liver cancer, lung cancer, pancreatic cancer, prostate cancer, stomach cancer, testicular cancer, and thyroid cancer.