One well-known example is [miR-21](https://), a microRNA frequently overexpressed in various cancers. It can suppress the expression of tumor suppressor genes such as PTEN and PDCD4, promoting tumor growth and survival. Another example is [HOTAIR](https://), a long non-coding RNA associated with poor prognosis in breast cancer. HOTAIR can modify chromatin states to repress tumor suppressor genes. Additionally, [circRNA CDR1as](https://) can sequester miR-7, an important tumor suppressor, thereby enhancing oncogenic signaling pathways.
