It has been observed that the COX-2 expression level was higher in a statistically significant manner in the mucosa of patients with CRS without Ps as compared to the expression level in the mucosa and polyp tissue in patients with CRS with P. Moreover, in the polyp tissue the COX-2 expression level was significantly lower than in the mucosa with CRS with P (Table 2). Here, PTGS2 is linked to polyp.