12(S)-HHT (12(S)-HHTrE), a fatty acid produced via the arachidonic acid metabolic pathway of cyclooxygenase (COX), is an endogenous ligand and agonist of BLT2, and the 12(S)-HHT/BLT2 axis plays a role in the maintenance of homeostatic aspects of epithelial tissues and in inflammatory responses. 12(S)-HHT inhibits the p38 MAPK/NF-κB pathway through upregulation of MKP-1, leading to reduced IL-6 synthesis in UVB-irradiated HaCaT cells.