N-methyl-N-nitrosourea is primarily used in research settings as a potent alkylating agent to induce mutations in genetic studies. It is particularly valuable in cancer research for creating animal models of tumors, helping scientists understand the mechanisms of carcinogenesis and test potential therapeutic interventions. Additionally, it is employed in molecular biology to study DNA repair processes and the effects of DNA damage on cellular function. Due to its high reactivity and carcinogenic properties, it is handled with extreme caution and used exclusively in controlled laboratory environments.