Expression of nm 23 in the Primary Tumor and the Metastatic Regional Lymph Nodes of Patients with Gastric Cardiac Cancer 1

Tumor recurrence and distant metastasis are major causes of treatment failure in gastric cardiac cancer (GCC). Rapid growth of tumor cells and reduced expression of nm23, a metastatic suppressor gene, in tumor cells have been suggested as two important mechanisms for disease progression of GCC. Therefore, to determine the prognostic value of nm23 expression in GCC, we used immunohistochemistry to examine the expression of nm23 in the pathological sections of both gastric cancer and metastatic lymph nodes from 24 stage III patients. Twenty-two patients had total gastrectomy, and two patients had proximal subtotal gastrectomy with a D2 dissection. Postoperative adjuvant therapy was provided, and the clinical responses were followed routinely. Clinical correlation was evaluated byx with Fisher’s exact test and survival by log-rank test. Our results show that the reduced nm23 expression in the primary tumor and in the nodal metastasis is the most useful marker for the poor prognosis of GCC following surgery. INTRODUCTION GC is the fourth leading cause of cancer death in Taiwan (1). The annual incidence rate has varied from 3 per 100,000 men to 25 per 100,000 men, depending upon genetic vulnerability, diet, and environmental factors. Although surgery is a curative treatment for the early-stage GC, most patients present with advanced disease (2–6). Furthermore, poor prognosis is compounded by the rapid growth of tumor and spreading of cancer cells as well as disease-associated malnutrition and cachexia. It is worth noting that the prognosis of patients with GCC is worse than that of patients with distally located GC (7). The effort of multiple therapeutic modalities was not beneficial for patients at the late stage (8–12). Therefore, a method for identifying the disease progression of GCC and the potential of cancer cell spreading is important for commencing early treatment and increasing survival. Rapid growth of tumor cells has been suggested as the major cause for treatment failure in GC surgery (13, 14). It has also been associated with tumor vascularity as well as proliferation-dependent tumor recurrence and distant metastasis (8–12). Nonetheless, patients at the early stage could have rapid tumor recurrence following surgery, and patients at the late stage could survive for a long period of time after treatment, suggesting that intrinsic factor(s) could play a role in this difference. The increasing evidence has indicated that nm23 has antimetastasis activity, suggesting that reduced expression of nm23 is associated with the early metastasis (15–20). Interestingly, the increased number of regional lymph node metastases was further shown to be correlated with the poor prognosis of GC (21). The decreased survival rate noted in the malignancy would then suggest a role of lymph node in association with the disease progression. However, the significance of nm23 expression in the primary GC as well as that in the metastatic regional lymph node for monitoring the disease activity and the response to the treatment is not yet known. This study was initiated to address this question. Therefore, in this report, we compared more extensively the difference of nm23 expression between the primary GC and the metastatic regional lymph node in 24 patients with stage III GCC. We also examined a variety of parameters that were associated with the prognosis together with the correlation between these parameters and nm23 expression. PATIENTS AND METHODS Tissue Specimens. From January 1984 to December 1995, tissue specimens and 335 regional lymph nodes (range, 4–43 for each patient) from 24 patients with GCC at stage III were collected. Twenty-two patients had total gastrectomy, and two patients had proximal subtotal gastrectomy with a D2 dissection, including N1 (perigastric) and N2 (splenic, left gastric artery, and celiac axis) lymph nodes. Clinical stage of the disease was classified according to the guidelines of the TNM system (22). Patients with lymph node involvement and patients with locoregional recurrence were irradiated with 22 Gy at the afflicted areas. Those with distant metastasis were treated with chemotherapy (2–7). After treatment, all patients were followed routinely. Before surgery, written informed consent was obtained from every patient, and a single-blind procedure was followed to carry out immunohistochemistry and statistic analReceived 9/17/98; revised 2/8/99; accepted 2/22/99. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisementin accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1 This study was supported by the National Science Council, Republic of China (Grant NSC 86-2314-B-182A-076). 2 To whom requests for reprints should be addressed, at 2 Yuh-Der Road, China Medical College Hospital, Taichung, Taiwan, Republic of China. Phone: 886-4-2052121 ext. 1974; Fax: 886-4-2029083; E-mail: 440506@ms15.hinet.net. 3 The abbreviations used are: GC, gastric cancer; GCC, gastric cardiac cancer. 1752Vol. 5, 1752–1757, July 1999 Clinical Cancer Research Research. on October 16, 2017. © 1999 American Association for Cancer clincancerres.aacrjournals.org Downloaded from Fig. 1 Immunohistochemical staining of nm23 expression in primary tumor ( A) and metastatic lymph node ( B). Original magnification,3100. 1753 Clinical Cancer Research Research. on October 16, 2017. © 1999 American Association for Cancer clincancerres.aacrjournals.org Downloaded from ysis. Antibodies used for immunological staining were specific to nm23-H1 (Santa Cruz Biotechnology, Santa Cruz, CA). Immunological staining was performed by an immunoperoxidase method, as described previously (23). Nonneoplastic gastric mucosa was used as the internal positive control. Lymph node from the tonsil was used as negative control. Statistical Analysis. The relationships between expression of nm23 and clinicopathological parameters (age, sex, size, Borr-mann type, differentiation, lymphovascular invasion, number of lymph nodes involved, and tumor depth) were analyzed by x analysis (or by Fisher’s exact test, when the expected number within any cell was less than or equal to five cases). Univariate proportional hazards regression was used to estimate the dependence of survival on each variable (24). Multivariate analysis was used to test the variable that has been selected by the above method to have the prognostic value. Survival curves were plotted with method of Kaplan and Meier (25). Statistical differences in survival between different groups were compared by the log-rank test (26).