MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and have been implicated in various diseases, including cancer. Recent research has focused on the presence of miRNAs in body fluids such as serum, plasma, and other bodily fluids, which may serve as non-invasive biomarkers for cancer detection and treatment response. miRNAs are involved in the pathogenesis of cancer and other diseases, and their expression is often altered in cancerous tissues compared to normal tissues. Studies have shown that miRNAs can act as oncogenes or tumor suppressors, depending on the cancer type and cellular context. The expression of miRNAs in body fluids has been extensively studied, and several miRNAs have been identified as potential biomarkers for cancer diagnosis, prognosis, and treatment response. For example, miR-21 is associated with poor survival in colon cancer, while miR-141 can distinguish prostate cancer patients from healthy individuals. miRNAs have also been detected in other body fluids such as saliva, urine, and tears, and their levels may correlate with various disease states. The stability of miRNAs in body fluids is important for their use as biomarkers, as they are resistant to degradation under various conditions. Exosomes, which are small membrane vesicles containing miRNAs, have been identified in blood and other body fluids, and their miRNA content may reflect the expression profile of the originating cells. The secretion of miRNAs by tumor cells can influence the surrounding microenvironment, promoting tumor progression. Techniques such as miRNA microarrays, quantitative real-time PCR, and deep sequencing are used to analyze miRNA expression in body fluids. However, challenges remain in standardizing these methods and ensuring the accuracy of miRNA-based biomarkers. Despite these challenges, miRNAs show promise as non-invasive biomarkers for cancer detection and treatment response. Further research is needed to validate the utility of miRNAs in clinical settings and to establish standardized protocols for their use in biomarker discovery and cancer research.MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and have been implicated in various diseases, including cancer. Recent research has focused on the presence of miRNAs in body fluids such as serum, plasma, and other bodily fluids, which may serve as non-invasive biomarkers for cancer detection and treatment response. miRNAs are involved in the pathogenesis of cancer and other diseases, and their expression is often altered in cancerous tissues compared to normal tissues. Studies have shown that miRNAs can act as oncogenes or tumor suppressors, depending on the cancer type and cellular context. The expression of miRNAs in body fluids has been extensively studied, and several miRNAs have been identified as potential biomarkers for cancer diagnosis, prognosis, and treatment response. For example, miR-21 is associated with poor survival in colon cancer, while miR-141 can distinguish prostate cancer patients from healthy individuals. miRNAs have also been detected in other body fluids such as saliva, urine, and tears, and their levels may correlate with various disease states. The stability of miRNAs in body fluids is important for their use as biomarkers, as they are resistant to degradation under various conditions. Exosomes, which are small membrane vesicles containing miRNAs, have been identified in blood and other body fluids, and their miRNA content may reflect the expression profile of the originating cells. The secretion of miRNAs by tumor cells can influence the surrounding microenvironment, promoting tumor progression. Techniques such as miRNA microarrays, quantitative real-time PCR, and deep sequencing are used to analyze miRNA expression in body fluids. However, challenges remain in standardizing these methods and ensuring the accuracy of miRNA-based biomarkers. Despite these challenges, miRNAs show promise as non-invasive biomarkers for cancer detection and treatment response. Further research is needed to validate the utility of miRNAs in clinical settings and to establish standardized protocols for their use in biomarker discovery and cancer research.