Hypoxia, a condition of low oxygen levels, plays a critical role in cancer progression, angiogenesis, metastasis, and resistance to therapy. It leads to dysfunctional vascularization and the acquisition of an epithelial-to-mesenchymal transition (EMT) phenotype, promoting cell mobility and metastasis. Hypoxia alters cancer cell metabolism and contributes to therapy resistance by inducing cell quiescence. It activates complex signaling pathways, including HIF, PI3K, MAPK, and NF-κB, which interact to enhance or diminish hypoxic effects. Understanding hypoxia's role in cancer is essential for developing new therapies targeting hypoxic tumor cells and their microenvironment. Hypoxia induces the HIF pathway, which regulates gene expression for angiogenesis, metastasis, and therapy resistance. HIF-1α and NF-κB pathways control over 1,000 genes, influencing cancer cell survival, migration, and metastasis. Hypoxia also promotes EMT, a process that increases cancer cell plasticity and metastatic potential. Hypoxia-induced EMT is associated with chemoresistance and radioresistance, as it enhances stem-like properties and cell cycle arrest. Hypoxia contributes to tumor angiogenesis by stimulating the formation of new blood vessels, which can be dysfunctional and leaky in tumors. This leads to a vicious cycle of hypoxia and angiogenesis, resulting in a highly hypoxic tumor environment. Anti-angiogenic therapies, such as bevacizumab, have shown promise but can also increase metastatic potential. Hypoxia also enhances metastasis by promoting EMT, increasing cell motility, and creating a pre-metastatic niche. Hypoxia induces therapy resistance by regulating cell cycle arrest, inhibiting apoptosis, and modulating autophagy and p53 activity. It also affects drug delivery and cellular uptake, contributing to chemoresistance. Hypoxia is a major feature of solid tumors and correlates with poor prognosis. Hypoxia-induced resistance is influenced by factors such as HIF-1α, NF-κB, and other signaling pathways. The tumor microenvironment, including stromal cells and immune cells, is also affected by hypoxia. Hypoxia can induce immunosuppression, allowing tumor cells to evade immune surveillance. Understanding hypoxia's role in the tumor microenvironment is crucial for developing targeted therapies. In conclusion, hypoxia plays a pivotal role in cancer progression, metastasis, and therapy resistance. Targeting hypoxia and its associated pathways offers new therapeutic opportunities for cancer treatment.Hypoxia, a condition of low oxygen levels, plays a critical role in cancer progression, angiogenesis, metastasis, and resistance to therapy. It leads to dysfunctional vascularization and the acquisition of an epithelial-to-mesenchymal transition (EMT) phenotype, promoting cell mobility and metastasis. Hypoxia alters cancer cell metabolism and contributes to therapy resistance by inducing cell quiescence. It activates complex signaling pathways, including HIF, PI3K, MAPK, and NF-κB, which interact to enhance or diminish hypoxic effects. Understanding hypoxia's role in cancer is essential for developing new therapies targeting hypoxic tumor cells and their microenvironment. Hypoxia induces the HIF pathway, which regulates gene expression for angiogenesis, metastasis, and therapy resistance. HIF-1α and NF-κB pathways control over 1,000 genes, influencing cancer cell survival, migration, and metastasis. Hypoxia also promotes EMT, a process that increases cancer cell plasticity and metastatic potential. Hypoxia-induced EMT is associated with chemoresistance and radioresistance, as it enhances stem-like properties and cell cycle arrest. Hypoxia contributes to tumor angiogenesis by stimulating the formation of new blood vessels, which can be dysfunctional and leaky in tumors. This leads to a vicious cycle of hypoxia and angiogenesis, resulting in a highly hypoxic tumor environment. Anti-angiogenic therapies, such as bevacizumab, have shown promise but can also increase metastatic potential. Hypoxia also enhances metastasis by promoting EMT, increasing cell motility, and creating a pre-metastatic niche. Hypoxia induces therapy resistance by regulating cell cycle arrest, inhibiting apoptosis, and modulating autophagy and p53 activity. It also affects drug delivery and cellular uptake, contributing to chemoresistance. Hypoxia is a major feature of solid tumors and correlates with poor prognosis. Hypoxia-induced resistance is influenced by factors such as HIF-1α, NF-κB, and other signaling pathways. The tumor microenvironment, including stromal cells and immune cells, is also affected by hypoxia. Hypoxia can induce immunosuppression, allowing tumor cells to evade immune surveillance. Understanding hypoxia's role in the tumor microenvironment is crucial for developing targeted therapies. In conclusion, hypoxia plays a pivotal role in cancer progression, metastasis, and therapy resistance. Targeting hypoxia and its associated pathways offers new therapeutic opportunities for cancer treatment.