The Expression of Topoisomerase II alpha in the Gastric Carcinoma

Kim, Sei Jong; Yoon, Chong Mann; Rew, Jong Sun; Choi, Sung Kyu; Park, Chang Soo; Koo, Cheol

Abstract

BACKGROUND AND AIMS: Topoisomerase IIa (Topo IIa) separates chromosomes at the end of mitosis and thus, is the target for various chemotherapeutic agents. Expression of this enzyme has been demonstrated to increase rapidly from the end of the S to G2/M phase and decrease after the completion of mitosis. Gastric cancer is the most frequent cancer in Korea. However, the expression of Topo IIa according to cell types of gastric cancer and correlation between expression of Topo IIa and prognosis of gastric cancer has not been reported yet.
METHODS
A retrospective analysis of 92 cases of gastric cancer was performed to evaluate the prognostic significance of clinicopathologic features such as pathologic type, depth of invasion, status of lymph node metastasis, clinical stages, mean survival time and survival rate according to the expression of Topo IIa and Ki-67 by immunohistochemical staining.
RESULTS
Positive cell ratio of Topo IIa was significantly correlated with that of Ki-67 in most of the specimens examined (R=0.75, p<0.001). The pattern of Topo IIa immunolocalization in adenocarcinomas was also essentially the same as that of Ki-67. Positive cell ratio of Topo IIa for well differentiated, moderately differentiated, poorly differentiated, mucinous and signet ring cell adenocarcinoma were 65.7+/-9.9%, 55.9+/-14.9%, 50.7 +/-14.1%, 57.5+/- 13.3%, and 46.7+/-20.2%, respectively. Significant difference in positive cell ratio of Topo IIa was observed between well differentiated and poorly differentiated adenocarcinorna (p<0.01). However, the expression of Topo IIa was not correlated to the depth of invasion, lymph node metastasis, mean survival time and 5 year survival rate.
CONCLUSIONS
These results suggest that expression of Topo IIa is related to the degree of tumor cell differentiation, but has no significant role in the prognosis of gastric cancer.