This book explores the groundbreaking potential of CRISPR/Cas9 gene-editing technology in revolutionizing cancer treatment. This collection of chapters delves into the application of CRISPR/Cas9 across a variety of cancers, including lung, breast, brain, gastric, pancreatic, colorectal, liver, prostate, bladder, cervical, ovarian, and bone cancers. Each chapter provides an in-depth analysis of how CRISPR/Cas9 can target and modify cancerous cells at the genetic level, offering the potential for highly personalized and precise therapies. The book also addresses the growing challenge of cancer drug resistance, detailing how CRISPR/Cas9 is being employed to study, understand, and potentially reverse resistance mechanisms, offering new hope for patients who have exhausted conventional treatment options. Furthermore, the integration of nanoparticles for efficient delivery of the CRISPR/Cas9 system is highlighted, providing a promising avenue for overcoming delivery challenges in cancer therapy. "This book provides a comprehensive and accessible guide to CRISPR/Cas9 genome editing for cancer treatment. It covers CRISPR/Cas9 editing across major cancer types, explores the potential of CRISPR/Cas9 in reversing drug resistance, and discusses strategies for delivering Cas9 to desired cell types. It is an invaluable resource for both experts and non-experts looking to enter this fast-moving field." Leslie Beh, Principal Investigator, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore Dr Kiavash Hushmandi is currently an Adjunct Assistant Professor at the Department of Epidemiology, University of Tehran, Iran. He received his PhD in Epidemiology from the University of Tehran. His research interests relate to molecular genetics, cancer biology, molecular epidemiology, cellular signaling, and public health. He has been among Top 2% of Scientists Worldwide by Stanford University for three consecutive years (2023–2025), and among the top 1% scientists in the Islamic World. Dr Alan Prem Kumar is an internationally recognized cancer biologist and academic leader at the Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore where he serves as Assistant Professor in the Department of Pharmacology, Assistant Dean (Graduate Studies), and Director of the Office of Postdoctoral Affairs. His research is at the forefront of translational oncology, focusing on uncovering the molecular drivers of metastasis in female reproductive cancers and advancing precision-guided therapeutic strategies. His pioneering contributions have been recognized globally. He is a Clarivate Highly Cited Researcher (World's Top 1%) for four consecutive years (2020–2023) and among the World's Top 2% Scientists as listed by Stanford University (2022–2025). A passionate mentor and educator, he is a three-time recipient of the NUS Graduate Mentor of the Year Award (2017, 2021, 2025), reflecting his deep commitment to nurturing the next generation of biomedical scientists. Beyond academia, he contributes his expertise to scientific advisory boards including the Sansad Mobile Swasthya Seva (Parliament of India), The Sparks Foundation (Singapore) and AUM Biosciences (Singapore). He maintains dynamic industry collaborations with leading pharmaceutical and biotech partners such as Davos Life Sciences, Daiichi Sankyo, Rexahn Pharmaceuticals, and DotBio, driving innovation in targeted drug discovery and protective cancer therapeutics. His work exemplifies the powerful intersection of academic excellence, translational science, and societal impact.