Extracellular vesicle-mediated pre-metastatic niche formation via altering host microenvironments Extracellular vesicles (EVs) secreted by cancer cells play a key role in the formation of pre-metastatic niches (PMNs), which are microenvironments that support the growth of tumor cells in distant organs. EVs carry various molecules, including mRNAs, small RNAs, microRNAs, DNA fragments, proteins, and metabolites, which help establish metastasis-supportive microenvironments. These EVs can educate stromal cells in secondary sites to create a favorable environment for tumor cell colonization. The formation of PMNs involves complex interactions between tumor cells and the host microenvironment, including the activation of stromal cells, the promotion of angiogenesis, and the modulation of immune responses. EVs can also alter the metabolic environment of organs, which is crucial for tumor metastasis. The mechanisms underlying EV-mediated PMN formation are still not fully understood, but recent studies have shown that EVs can influence the development of PMNs by enhancing angiogenesis, vascular permeability, and stromal reprogramming. Additionally, EVs can induce immunosuppression, which helps cancer cells evade immune surveillance. The role of EVs in PMN formation is an important area of research, as it may lead to new strategies for preventing cancer metastasis.Extracellular vesicle-mediated pre-metastatic niche formation via altering host microenvironments Extracellular vesicles (EVs) secreted by cancer cells play a key role in the formation of pre-metastatic niches (PMNs), which are microenvironments that support the growth of tumor cells in distant organs. EVs carry various molecules, including mRNAs, small RNAs, microRNAs, DNA fragments, proteins, and metabolites, which help establish metastasis-supportive microenvironments. These EVs can educate stromal cells in secondary sites to create a favorable environment for tumor cell colonization. The formation of PMNs involves complex interactions between tumor cells and the host microenvironment, including the activation of stromal cells, the promotion of angiogenesis, and the modulation of immune responses. EVs can also alter the metabolic environment of organs, which is crucial for tumor metastasis. The mechanisms underlying EV-mediated PMN formation are still not fully understood, but recent studies have shown that EVs can influence the development of PMNs by enhancing angiogenesis, vascular permeability, and stromal reprogramming. Additionally, EVs can induce immunosuppression, which helps cancer cells evade immune surveillance. The role of EVs in PMN formation is an important area of research, as it may lead to new strategies for preventing cancer metastasis.