Background <p>Cancer remains one of the leading causes of human death worldwide. Small extracellular vesicles (sEVs) are nanoscale particles that play important roles in intercellular communication in cancer and represent a valuable source for cancer biomarker discovery. Tissue-derived small extracellular vesicles (Ti-sEVs) are a specific subtype of sEVs and have attracted increasing attention as an emerging research area in cancer diagnostics and therapeutics. Recent progress has highlighted the distinct advantages of Ti-sEVs, including greater cancer specificity, minimal exogenous contamination, enhanced potential for cancer biomarker discovery and understanding tumour microenvironment (TME) dynamics.</p> Methods <p>This review summarises recent advancements in the preparation, isolation, and characterization of Ti-sEVs. It further discusses current knowledge of their biological functions within the TME and critically evaluates their emerging application in cancer diagnosis and prognosis.</p> Conclusion <p>Ti-sEVs offer unique opportunities for cancer biomarker discovery and translational research. However, key challenges remain, including tissue processing variability, methodological standardization, and technical barriers to clinical implementation. Addressing these issues will be essential to realize the full potential of Ti-sEV-based diagnostics and therapeutics and to guide future research in this rapidly evolving field.</p>