Thyroid cancer's frequency has skyrocketed in recent decades, making it one of the most prevalent endocrine cancers overall. There were 586,000 instances of thyroid cancer in 2020, according to estimates. About 3% of all people with cancer had this diagnosis. According to the World Health Organization, by 2020, 685,000 women will be undergoing treatment for breast cancer. There is still a lack of knowledge regarding the biology of carcinoma, despite the fact that it is one of the world's leading causes of mortality. MicroRNAs (miRNAs; miRs) are non-coding RNAs that may inhibit gene expression by cleaving the 3′ untranslated regions of mRNA. Due to these characteristics, they may be able to impede the process of protein synthesis. MiRNA regulates a wide variety of cellular pathways thought to have a role in cancer development. The examination of global miRNA expression in cancer indicated regulatory activity via up regulation and down-regulation in numerous malignancies, including thyroid cancer and breast cancer. Thyroid cancer miRNAs modulate MAPK, PI3K, and the RAS pathway, three cancer-related signaling pathways. Cell proliferation and cell cycle progression in breast cancer were regulated by miRNA via the cyclin protein family, protein kinases and their inhibitors, and other growth promoters or suppressors. The purpose of this article is to review the therapeutic modulation of important miRNA expressions in the treatment of thyroid and breast cancer.