RESUMO
Objective To analyze the expression of cyclooxygenase-2 (COX-2) in the patients with snow-white sign of advanced colorectal adenoma (ACA) and explore its clinical significance.Method Western blotting was employed to determine the expression of COX-2 in the adenoma tissue and the normal tissue adjacent to the adenoma tissue (>5 cm away from the distal end of the adenoma tissue) of 40 ACA patients with snow-white sign and 40 ACA patients without snow-white sign.Results The appearance of snow-white sign in ACA patients was associated with patient age (P=0.001) and not associated with sex,smoking history,drinking history,ethnic groups,family history of colorectal cancer,abdominal pain,diarrhea,constipation,fecal occult blood,or tumor markers (all P>0.05).Snow-white sign mainly appeared in the ACA patients with multiple adenomas (P=0.004),large adenomas (P=0.006),adenomas in distal colon (P=0.015),protruding polyps (P=0.044),and late-stage pathology (P=0.010).The occurrence of snow-white sign showed no difference in the ACA patients with different results of Japan NBI Expert Team classification (P=0.502).The expression of COX-2 in the adenoma tissue was higher than that in the adjacent normal tissue in the patients with and without snow-white sign (P<0.001,P=0.004).The patients with snow-white sign had higher expression of COX-2 protein in the adenoma tissue than the patients without snow-white sign (P=0.001).The expression of COX-2 protein in the adjacent healthy tissue had no significant difference between the patients with and without snow-white sign (P=0.603).Conclusions Snow-white sign is more like to appear in the ACA patients with young age,multiple and large adenomas,adenomas in distal colon,protruding polyps,and late-stage pathology.Moreover,the expression of COX-2 in the ACA patients with snow-white sign is significantly higher than that in the ACA patients without snow-white sign.The adults with snow-white sign are prone to cancerization than those without snow-white sign.