PTGS2 and pachyonychia congenita: miRNAs play crucial roles in critical cellular processes such as cell proliferation, differentiation, cell cycle progression, apoptosis, angiogenesis, the epithelial-mesenchymal transition (EMT), and metastasis during cancer progression.47 Hao et al. showed that miRNA-101 inhibited PC cell proliferation by inhibiting cyclooxygenase-2 (COX-2) gene expression, inhibiting the activation of the COX-2/PGE2/EGFR pathway, which mediates cell proliferation during inflammation.48 COX-2 is an inducible isozyme of COX, a key enzyme in converting arachidonic acid to prostaglandins and other eicosanoids.