Breast cancer (BC) is one of the most common diseases in women and can affect various aspects of society, including psychological, economic, and family dynamics. Established tumor cells use multiple methods to spread and develop tumor tissue. Understanding these mechanisms can aid in diagnosis, treatment, follow-up, and patient care. Tumor cells can produce exosomes that mediate intercellular communication, leading to tumor progression. MicroRNAs (miRNAs) are among the primary mediators of breast cancer progression, diagnosis, and treatment via exosomes, playing essential roles in regulating various cellular mechanisms in target cells. After being produced, exosomes are observed in the tumor microenvironment (TME) and blood, and after being taken up by various cells, they play a role in mechanisms that promote tumor growth, including proliferation, invasion, angiogenesis, and distant metastasis.

Given the presence of tumor cell-derived exosomes (TEXs) in the blood, they can be used for the early diagnosis of breast cancer. Furthermore, although they have pathogenic effects, exosomes produced by tumor cells are rich sources of tumor antigens and can be utilized in breast cancer treatment after various manipulations and engineering methods. Other cellular sources, including immune cells, also produce exosomes for the treatment of breast cancer. Immune cell-derived exosomes (IEXs) can prevent tumor spread by activating antitumor immune responses through the induction of apoptosis, inhibition of tumor cell proliferation, and inhibition of tumor cell invasion.