Quarfloxin (CX-3543) is primarily used in cancer research and treatment due to its ability to disrupt the interaction between nucleolin and G-quadruplex structures in DNA. This disruption inhibits the transcription of certain oncogenes, making it a potential therapeutic agent for cancers that rely on these genes for growth and survival. It has shown promise in preclinical studies for targeting cancers such as lymphoma and leukemia. Additionally, its mechanism of action is being explored for potential applications in other diseases where G-quadruplex structures play a critical role, such as certain viral infections and neurodegenerative disorders. Research is ongoing to further understand its efficacy and safety in clinical settings.