[Significance of COX-2, p53, proliferating cell nuclear antigen and nm23 expressions in gastric cancer and its behavior].

BACKGROUND & OBJECTIVE: Molecular biological studies indicated that abnormal expression of cyclooxygenase-2(COX-2), p53, proliferating cell nuclear antigen(PCNA), and nm23 correlate with the development of gastric cancer, but the relationship between abnormal expression of above gene proteins and the biological behavior of gastric cancer was not yet clear. This study was designed to investigate the relationship between expressions of COX-2, p53, PCNA, and nm23 and the clinicopathological behavior in gastric cancer.

METHODS

The expressions of COX-2, p53, PCNA, and nm23 were detected by using immunohistochemical(SP) method.

RESULTS

(1) The overexpression rate of COX-2 in gastric cancer was 70.4% (50/71), and the overexpression of COX-2 was correlated to tumor size, gross morphology, histological type, lymph node metastases, and clinicopathological stage of gastric cancer (P < 0.05, or P < 0.01). (2) The overexpression rates of p53 and PCNA in 71 surgically removed specimens from the patients with gastric cancer were 74.6% and 78.9%, respectively. And the expressions of p53 (86.7%) and PCNA (88.8%) in gastric cancer patients with lymph node metastasis were significantly higher than those in patients without lymph node metastasis (53.8% and 61.5%) (both, P < 0.05), respectively. Moreover, expressions of p53(52.2%) and PCNA(60.9%) in stage I + II patients were lower than those(85.4% and 87.5%) in stage III + IV (both, P < 0.05). (3) The low-expression of nm23 in gastric cancer was 71.8%, and its low-expression rate of nm23 in patients without lymph node metastasis(88.5%) and in stage I + II (91.3%) were much higher than those in the patients with lymph node metastasis (62.2%) and in stage III + IV (62.5%) (respectively, P < 0.05). (4) The differences of histological types, depth of invasion, lymph node metastasis and clinical stage were significantly different(P < 0.05 or P < 0.001), between the patients with two or more genes expression of COX-2, p53, PCNA, and nm23 and those with less one gene expression.

CONCLUSION

Our results suggest that abnormal expressions of COX-2, p53, PCNA, and nm23 associate with malignant potential, lymph node metastasis and clinical stage, and they might therefore play a role in development of gastric cancer.