miRNAs in radiotherapy resistance of cancer; a comprehensive review

While intensity-modulated radiation therapy-based comprehensive therapy increases outcomes, cancer patients still have a low five-year survival rate and a high recurrence rate. The primary factor contributing to cancer patients' poor prognoses is radiation resistance. A class of endogenous non-coding RNAs, known as microRNAs (miRNAs), controls various biological processes in eukaryotes. These miRNAs influence tumor cell growth, death, migration, invasion, and metastasis, which controls how human carcinoma develops and spreads. The correlation between the unbalanced expression of miRNAs and the prognosis and sensitivity to radiation therapy is well-established. MiRNAs have a significant impact on the regulation of DNA repair, the epithelial-to-mesenchymal transition (EMT), and stemness in the tumor radiation response. But because radio resistance is a complicated phenomena, further research is required to fully comprehend these mechanisms. Radiation response rates vary depending on the modality used, which includes the method of delivery, radiation dosage, tumor stage and grade, confounding medical co-morbidities, and intrinsic tumor microenvironment. Here, we summarize the possible mechanisms through which miRNAs contribute to human tumors' resistance to radiation.