Relationship between expression of p21~(WAF1) and p53 gene in gastric carcinoma

Objective To investigate the relationship of expression of p21 WAF1 and p53 gene in gastric carcinoma. Methods The expression of p21 WAF1 and p53 protein was examined by streptavidin-peroxidase conjugated method (S-P) in gastric carcinoma. Results The positive expression rate of p21 and p53 were found in 100% and 0% of normal mucosa, in 92.5% and 15.0% of dysplasia and in 39.8% and 56.5% of gastric carcinoma,respectively. There were 5.0% cases who had a p53 positivity and p21 negativity, whereas 82.5% cases had a p53 negativity and p21 positivity in total 40 cases of dysplasia (P0.05). The expression of p53 increased from well-differentiated (36.7%) to poorly-differentiated (78.2%) (P0.05), while that of p21 decreased from (63.3%) to (32.7%) in 108 cases of gastric carcinoma(P0.05), and they expressed reversely in 48.1% of gastric carcinoma. The expression of p21 in superficial muscle invasion (60.0%) was lower than that in deep muscle invasion (35.2%)(P0.05). The expression of p21 and p53 in paired primary and lymph node metastasis carcinoma (35.3% and 70.6%)coincidently, different from non-metastasis carcinoma (62.5% and 42.5%) significantly (P 0.05). The expression of p21 in TNM staging Ⅰ (60.0%) and Ⅱ (56.2%) was higher than that in Ⅲ (27.9%) and Ⅳ ( 22.2%) (P0.05), whereas the expression of p53 did not correlate to the TNM staging. Conclusion The expression of p21 WAF1 protein depends on p53 protein largely in normal gastric mucosa and dysplasia, but not considerably in gastric carcinoma. The loss of p21 expression and abnormal expression of p53 is related to carcinogenesis, differentiation and metastasis, and the loss of p21 expression is related to invasion and clinical staging in gastric carcinoma intimately.