Moreover, there is evidence that miR-21 inhibits the translation of TGFβ-1 mRNA in various diseases, including endometriosis [81,82,84,85], and the post-transcriptional regulation of miR-21 via SMAD3 plays a key role in its upregulation and the development of fibrosis [45]. This evidence concerns the gene SMAD3 and endometriosis.