This study investigates how well treatment directed by genetic testing works in children with certain cancers like solid tumors, non-Hodgkin lymphomas, or histiocytic disorders. These are conditions where cells grow uncontrollably in different parts of the body. The study aims to find out if specific changes in genes can be targeted with certain cancer-fighting drugs.

Participants will undergo genetic testing to identify any gene changes that can be targeted with specific treatments. This involves using data from medical tests to see if the tumors have specific gene alterations that can be treated with pathway-targeting agents. These agents are drugs designed to interfere with the pathways that cancer cells use to grow.

• Who can participate: Children with recurrent or hard-to-treat solid tumors, non-Hodgkin lymphomas, or histiocytic disorders can join. They must have a sample of their tumor available for testing and meet certain health criteria.
• Study details: Participants will have genetic testing to see if their cancer has specific gene changes. They may receive a treatment that targets these changes if eligible. A placebo, which is a substance that looks like the treatment but has no active ingredients, is not used in this study.