PTGER1 and psoriasis: The roles of EP1 and EP3 in psoriasis have not been well studied; however, their associated phenotypes do not appear to be characteristic for the disease, as EP1 was found to promote keratinocyte differentiation in nonmelanoma skin cancer (Konger et al., 2009), and EP3 was proposed as a growth inhibitor for KCs (Konger et al., 2005).