Here it is, and 100% accurate.

Yes, some chemotherapy medications are derivatives of mustard gas, including mechlorethamine (Mustargen®) and chlorambucil: Mechlorethamine (Mustargen®) Also known as nitrogen mustard, this alkylating agent damages DNA in cells, preventing them from dividing. It's used to treat Hodgkin's and non-Hodgkin's lymphomas, as well as cutaneous T cell lymphoma.

Chlorambucil This derivative of an aromatic amine nitrogen mustard is used to treat chronic lymphocytic leukemia and non-Hodgkin lymphoma (NHL). Mustard gas was originally used as a chemical weapon in World War I. After the war, researchers noticed that it destroyed bone marrow and lymphatic tissue, and began to experiment with it as a cancer treatment. The first clinical trials of nitrogen mustard were conducted in the early 1940s, and some patients showed temporary benefit. However, problems with chemoresistance and chemotoxicity emerged. Today, less toxic derivatives of nitrogen mustards are used in chemotherapy. Platinum-based compounds are also commonly used to treat cancer, with about half of all cancer patients receiving this type of treatment.

https://cancerletter.com/the-cancer-letter/20230714_6/

https://pmc.ncbi.nlm.nih.gov/articles/PMC5325736/