text: Since cancer cells, in general, proliferate faster and with less error-correcting than healthy cells, cancer cells are more sensitive to DNA damage—such as being alkylated. Alkylating agents are used to treat several cancers. However, they are also toxic to normal cells (cytotoxic), particularly cells that divide frequently, such as those in the gastrointestinal tract, bone marrow, testicles and ovaries, which can cause loss of fertility. Most of the alkylating agents are also carcinogenic.
  History
  Before their use in chemotherapy, alkylating agents were better known for their use as sulfur mustard, ("mustard gas") and related chemical weapons in World War I. The nitrogen mustards were the first alkylating agents used medically, as well as the first modern cancer chemotherapies. Goodman, Gilman, and others began studying nitrogen mustards at Yale in 1942, and, following the sometimes dramatic but highly variable responses of experimental tumors in mice to treatment, these agents were first tested in humans late that year.  Use of methyl bis (B-chloroethyl)emine hydrochloride (mechlorethamine, mustine) and tris (B-chloroethy) amine hydrochloride for Hodgkin's disease lymphosarcoma, leukemia, and other malignancies resulted in striking but temporary dissolution of tumor masses.  Because of secrecy surrounding the war gas program, these results were not published until 1946. These publications spurred rapid advancement in the previously non-existent field of cancer chemotherapy, and a wealth of new alkylating agents with therapeutic effect were discovered over the following two decades.