Regarding the upregulation of COX-2 in NP tissues, a study has shown that an increase of the COX-2 gene expression can be linked to the development of NPs in patients with CRS and the -14C/G MET gene polymorphism and -765G/C genotype of COX-2 can be associated with an increased risk of the occurrence of CRS with NPs in the Polish population35,36. The gene discussed is PTGS2; the disease is congenital rubella syndrome.