There are a number of inflammatory markers that have been shown to be affected in OLP [1,2,3,36], but we have focused upon COX-2 simply because COX-2-derived prostaglandins and/or COX-2 itself are modulated by PEA treatment in vitro [15] and in vivo [14], and that PTGS2, COX-2 and PG levels are known to be increased in OLP [4,5,6,7]. This evidence concerns the gene PTGS2 and oral lichen planus.