PIWI-interacting RNAs as novel biomarkers for diagnosis and treatment of breast cancer

Introduction: Breast cancer is one of the most leading cause of cancer-related deaths among women worldwide. Currently, there are several therapeutic and diagnostic methods for detecting and treating breast cancer patients. However, we are still facing some limitations in the fields of diagnosis and treatment. Therefore, studying the molecular mechanisms involved in breast cancer could lead to providing better care for patients suffering from this disease. Recently, non-coding RNAs have attracted a lot of attention in cancer researches due to their considerable roles in the development and progression of cancers as well as drug resistance. PIWI-interacting RNAs (piRNAs) which are a subclass of non-coding RNAs have been shown to have remarkable effects in breast cancer.Description: In this review, we provide a comprehensive overview providing studies concerned with the roles of piRNAs in breast cancer. We discuss how piRNAs can be involved in the development, progression, invasiveness, and metastasis of this disease. Moreover, findings of piRNAs which serve as diagnostic and prognostic biomarkers are summarized in this paper.Conclusion: Findings demonstrate that the expressions of some piRNAs are different in breast cancer compared to healthy breast tissue. While some of them are overexpressed, some other ones are reported to be downregulated or completely absent. Multiple piRNAs are associated with proliferation, invasion, and lymph node positivity of breast cancer. PiRNs can cause inhibitory effects on the metastasis of breast cancer. Moreover, several piRNAs alter the progression of the cell cycle. It is suggested that piRNAs act as tumor suppressors. in addition, they serve as a breast tumor marker. Studies indicated that the impacts of chemotherapeutic drugs on breast tumor can be enhanced by synergistic effects of piRNAs. Altogether, we believe that piRNAs are potential biomarkers which can be used in both diagnosis and treatment of breast cancer.