Relapsed Solid Tumor Malignancies

Background: Myeloid cells are a type of immune cell found in most tumors. Interleukin 12 (IL-12) is a protein that helps the immune system kill tumor cells. Researchers want to know if myeloid cells that have been genetically engineered to produce IL-12 (IL-12 GEMys) can activate the immune system to attack cancer cells in solid tumors. Objective: To test IL-12 GEMys in people with cancer. Eligibility People aged 18 years and older with cancer that returned or failed to respond to treatment. Design: Participants will be screened. They will have a physical exam with blood tests. They will have tests of their heart and lung function. They will have imaging scans of their tumors. A sample of tumor tissue may be taken. Participants will have daily injections for few days to prepare them to undergo leukapheresis: Blood will be taken from the body through a needle inserted into a vein. The blood will pass through a machine that separates out stem cells. The remaining blood will be returned to the body through a different needle. The collected stem cells will be modified in a lab to create IL-12 GEMys. Participants will check in to the hospital. They will receive drugs for 5 days to prepare their body for the treatment. Then they will have their own IL-12 GEMys infused through a needle inserted into a vein. They will stay in the hospital until they are well enough to go home. This may be 7 to 14 days or longer. Some participants may receive a second treatment with IL-12 GEMys within 2 years after the first. Participants will have follow-up visits for about 5 years. These will include imaging scans and blood tests.