The article reviews the mechanisms of cancer drug resistance, which is a complex process influenced by various factors such as genetic differences, tumor heterogeneity, and the tumor microenvironment. The review highlights several key mechanisms, including multi-drug resistance, cell death inhibition, altered drug metabolism, epigenetic changes, enhanced DNA repair, and gene amplification. These mechanisms can lead to treatment failures with common chemotherapy agents in different types of cancers. The authors also discuss the role of cancer stem cells in drug resistance and the importance of understanding these mechanisms to develop novel strategies for overcoming drug resistance. Additionally, the article explores the potential of combining epigenetic drugs with conventional chemotherapy and using RNA interference (RNAi) to target specific genes involved in drug resistance. The review concludes by emphasizing the need for further research to improve the effectiveness of cancer treatments.The article reviews the mechanisms of cancer drug resistance, which is a complex process influenced by various factors such as genetic differences, tumor heterogeneity, and the tumor microenvironment. The review highlights several key mechanisms, including multi-drug resistance, cell death inhibition, altered drug metabolism, epigenetic changes, enhanced DNA repair, and gene amplification. These mechanisms can lead to treatment failures with common chemotherapy agents in different types of cancers. The authors also discuss the role of cancer stem cells in drug resistance and the importance of understanding these mechanisms to develop novel strategies for overcoming drug resistance. Additionally, the article explores the potential of combining epigenetic drugs with conventional chemotherapy and using RNA interference (RNAi) to target specific genes involved in drug resistance. The review concludes by emphasizing the need for further research to improve the effectiveness of cancer treatments.