DNA Alkylator/Crosslinker is a class of chemical drugs that interfere with DNA replication and transcription by adding alkyl groups to DNA molecules or forming DNA cross-links. Family members include nitrosoureas, cyclophosphamide, and others. These drugs primarily function in the cell nucleus, disrupting DNA structure, triggering cellular repair mechanisms, or inducing cell death for cancer treatment. They participate in the DNA damage response signaling pathway, affecting cell cycle checkpoints and apoptotic pathways. The effectiveness and degree of side effects of such drugs may vary due to individual genetic differences. Genetic variations in DNA repair capacity genes may influence drug sensitivity and resistance.