PTGS2 and infectious otitis media: Consistently, because expressions of both EP2 and COX-2 are induced and become detectable in neutrophils and TAFs in the colon of AOM-DSS model during the development of the disease and genetic deletion of EP2 greatly suppressed COX-2 expression in these two types of cells [12], EP2 and COX-2 presumably have inter-dependency in vivo.