MicroRNAs (miRNAs), a class of non-coding RNAs, play a critical role in regulating gene expression and have demonstrated significant potential as biomarkers in cancer research. This review explores the role of miRNAs in tumorigenesis, invasion, and metastasis, highlighting their altered regulation in various cancers, including lung, breast, liver, colorectal, and prostate cancer. miRNA expression patterns analysis helps clinicians in early cancer diagnosis, classification, and therapeutic monitoring. The stability of miRNAs in body fluids makes them ideal candidates for liquid biopsy, offering a non-invasive tool for cancer detection and prognosis assessment. Despite the promising clinical applications, challenges remain in the standardization of detection methods and integration of multi-omics data. Results are variable because different detection platforms, including qPCR, microarray and sequencing methods which have varying sensitivity and specificity. However, integrating multi-omics data comes with additional technological challenges because it calls for sophisticated bioinformatics tools to manage intricate and huge datasets. Further advancements are expected to establish miRNAs as a robust foundation for personalized cancer therapy.