Immunohistochemical expression and significance of NM23 suppressor protein in primary gastric adenocarcinoma.

NM 23 protein was originally identified as a metastasis suppressor protein. The expression of NM23 has been correlated with tumour metastatic potential in various human carcinoma, mostly in ductal breast and colorectal carcinomas. Evidence for their expression in gastric cancer is rather contradictory, both for protein expression status and prognostic value. This study was done to analyze the immunohistochemical expression of NM23 in gastric carcinoma, and correlation of the degree of staining with clinicopathological parameters was investigated. In a retrospective immunohistochemical study specimens obtained from 56 gastric cancer patients who had undergone gastrectomy with perigastric lymphadenectomy were analysed, in correlation with classical clinical-pathological parameters of tumours, WHO-, Lauren-, Goseki-, and Ming- classification. NM 23 gene expression was compared in gastric adenocarcinoma and tumour-adjacent non-neoplastic gastric mucosa. A semiquantitative immunostaining evaluation (score 0-3) was used, counting the percentage of stained cells. Statistical analysis was performed using Kolmogorov-Smirnov test, and Spearman rank correlation test. The investigated group consisted of 40 males and 16 females (2.5:1) with a mean age of 63 years (range: 48-81 years). The percentage of positive expression of NM23 (score 3) were in 30 (53.5%) specimens in non-neoplastic mucosa in adjacent gastric carcinoma, and negative (score 0-2) in all 56 (100%) specimens of gastric adenocarcinoma. NM23 expression was higher in non-neoplastic mucosa than in adjacent gastric adenocarcinoma tissue (p<0.0001). NM23 protein expression did not correlate with gender (p=0.115), tumour size (p=0.844), tumour grade (p=0.172), lymphovascular invasion (p=0.606), lymph node metastases (p=0.311), Lauren classification (p=0.426), Goseki classification (p=0.458) and Ming classification (p=0.212). Our series did not show a significant correlation between NM23 expression and analysed clinico-pathological variables, but these results suggest that protein NM23 may have a role in gastric carcinoma pathogenesis.