Mustard gas was used during the trench warfare of World War I. This blistering agent was the most dreaded of all the poison gases used during the war because gas masks offered no protection. The gas itself tended to linger in low areas and did not disperse. According to WorldWar1.com, a soldier seeking shelter in low areas "could find himself blinded, with skin blistering and lungs bleeding."
The International Union of Pure and Applied Chemistry is called IUPAC. IUPAC sets the standards for naming chemical compounds. The second edition of the "IUPAC Compendium of Chemical Terminology" reports that mustard oil is an archaic name for isothiocyanate compounds. The mustard in your refrigerator contains isothiocyanate compounds. Mustard gas is derived from allyl isothiocyanate.
In addition to being used to prepare mustard gas, chemical derivatives of allyl isothiocyanate are used to make many older anticancer drugs, such as bendamustine and mechlorethamine. Doctors realized that mustard gas lowered white blood cell counts and tried to use this effect therapeutically. The landmark paper on the use of nitrogen mustard to treat leukemia, Hodgkin's lymphoma and lymphosarcomas was published in the September 1946 issue of the "Journal of the American Medical Association."
Eating lots of mustard will not cure cancer any more than being exposed to mustard gas will boost your health. Learning about the origins of words can provide fascinating connections between seemingly unrelated things such as mustard gas, the mustard plant and cancer drugs. However, such connections do not necessarily give rise to at home cures or alternative medications.