Topoisomerase II (Top2) is a critical enzyme involved in DNA replication, transcription, and chromosome segregation. It plays a key role in maintaining genomic integrity, but its inhibition is a key strategy in cancer chemotherapy. Drugs targeting Top2 are divided into two classes: Top2 poisons, which generate covalent DNA-protein complexes, and catalytic inhibitors, which block Top2 activity without forming such complexes. Top2 poisons, such as etoposide and doxorubicin, are highly effective in many cancers but can lead to secondary malignancies. Recent studies highlight the importance of understanding Top2's role in drug resistance and the need to minimize toxicities while maximizing therapeutic efficacy. Top2 poisons, like etoposide, cause DNA strand breaks and trigger DNA damage responses, leading to apoptosis. They can also induce single-strand breaks, which may contribute to cytotoxicity. The mechanism of action of Top2 poisons involves intercalation at the DNA cleavage site, disrupting the geometry required for religation. This process is critical for generating DNA damage and triggering repair pathways. However, the exact mechanism remains unclear, and recent structural studies have provided insights into how Top2 poisons interact with DNA. Top2 damage is repaired through various pathways, including nucleolytic excision of protein-DNA adducts and proteolytic degradation of Top2. Nucleolytic repair involves enzymes like Tdp1, which remove covalently bound Top2 from DNA. Proteolytic degradation of Top2 is also important, particularly in cells with low Top2 levels, where degradation is linked to DNA damage signaling. These repair mechanisms are essential for maintaining genomic stability and preventing cancer progression. Catalytic inhibitors of Top2, such as bisdioxopiperazines, do not form covalent complexes but inhibit Top2 activity. They are less toxic than Top2 poisons but may still contribute to secondary malignancies. Recent studies suggest that catalytic inhibitors could be useful in cancer therapy, particularly when combined with other agents to enhance efficacy and reduce toxicity. The future of Top2 as a drug target depends on developing more specific and less toxic agents. Research into Top2 isoforms, such as Top2α and Top2β, has shown that targeting Top2α may be more effective in certain cancers, while Top2β is associated with cardiotoxicity and secondary malignancies. New compounds, such as QAP1, are being developed to improve the specificity and potency of Top2 inhibitors. Combining Top2 targeting drugs with other agents, such as DNA repair inhibitors or proteasome inhibitors, may enhance therapeutic outcomes. Clinical trials have shown that combinations of Top2 poisons with other chemotherapeutic agents can be effective, but careful consideration of toxicity is necessary. The development of more targeted and less toxic Top2 inhibitors remains a key goal in cancer chemotherapy.Topoisomerase II (Top2) is a critical enzyme involved in DNA replication, transcription, and chromosome segregation. It plays a key role in maintaining genomic integrity, but its inhibition is a key strategy in cancer chemotherapy. Drugs targeting Top2 are divided into two classes: Top2 poisons, which generate covalent DNA-protein complexes, and catalytic inhibitors, which block Top2 activity without forming such complexes. Top2 poisons, such as etoposide and doxorubicin, are highly effective in many cancers but can lead to secondary malignancies. Recent studies highlight the importance of understanding Top2's role in drug resistance and the need to minimize toxicities while maximizing therapeutic efficacy. Top2 poisons, like etoposide, cause DNA strand breaks and trigger DNA damage responses, leading to apoptosis. They can also induce single-strand breaks, which may contribute to cytotoxicity. The mechanism of action of Top2 poisons involves intercalation at the DNA cleavage site, disrupting the geometry required for religation. This process is critical for generating DNA damage and triggering repair pathways. However, the exact mechanism remains unclear, and recent structural studies have provided insights into how Top2 poisons interact with DNA. Top2 damage is repaired through various pathways, including nucleolytic excision of protein-DNA adducts and proteolytic degradation of Top2. Nucleolytic repair involves enzymes like Tdp1, which remove covalently bound Top2 from DNA. Proteolytic degradation of Top2 is also important, particularly in cells with low Top2 levels, where degradation is linked to DNA damage signaling. These repair mechanisms are essential for maintaining genomic stability and preventing cancer progression. Catalytic inhibitors of Top2, such as bisdioxopiperazines, do not form covalent complexes but inhibit Top2 activity. They are less toxic than Top2 poisons but may still contribute to secondary malignancies. Recent studies suggest that catalytic inhibitors could be useful in cancer therapy, particularly when combined with other agents to enhance efficacy and reduce toxicity. The future of Top2 as a drug target depends on developing more specific and less toxic agents. Research into Top2 isoforms, such as Top2α and Top2β, has shown that targeting Top2α may be more effective in certain cancers, while Top2β is associated with cardiotoxicity and secondary malignancies. New compounds, such as QAP1, are being developed to improve the specificity and potency of Top2 inhibitors. Combining Top2 targeting drugs with other agents, such as DNA repair inhibitors or proteasome inhibitors, may enhance therapeutic outcomes. Clinical trials have shown that combinations of Top2 poisons with other chemotherapeutic agents can be effective, but careful consideration of toxicity is necessary. The development of more targeted and less toxic Top2 inhibitors remains a key goal in cancer chemotherapy.