Expression of eukaryotic initiation factor 4E in gastric adenocarcinoma and its association with clinical outcome

Overexpression of eIF4E can result in oncogenic transformation and uncontrolled growth of mammalian cells, presumably by facilitating the expression of growth-control gene products, which are normally translationally repressed. Overexpression of eIF4E was present in human breast carcinoma and human head and neck squamous cell carcinoma, and may be of prognostic value in breast carcinomas. In order to elucidate the clinical significance of eIF4E expression, this study was conducted to quantify expression of eIF4E in human gastric cancer tissue and correlate them with clinicopathological factors and patient survival.

Specimens from sixty-nine patients with gastric adenocarcinoma were analyzed and eIF4E overexpression was quantified by Western blot analysis. Quantification of eIF4E levels in cancer was expressed relative to controls from non-tumorous mucosa of the same patients. Confirmation of eIF4E overexpression at the cellular level was performed using immunohistochemical staining. The association of clinicopathologic factors and survival with eIF4E expression was analyzed.

In non-tumorous parts of specimens, overexpression of eIF4E was always present in gastric glands but not in gastric pits lining mucosa, and it was also expressed in the areas of intestinal metaplasia and dysplasia. In the 69 specimens, the mean eIF4E expression was 5.77 +/- 8.55-fold (mean +/- standard deviation), ranged from from 0.1-fold to 38-fold. The degree of eIF4E expression appeared to be independent of invasion depth of tumor, lymph node metastasis, Lauren classification, Borrmann types, and Helicobacter pylori infection. Marked overexpression of eIF4E (more than seven-fold) was correlated with tumor vascular invasion (P = 0.046, Fisher exact-test). The survival rate of the patients with underexpression or mild overexpression of eIF4E (less than sevenfold) was significantly higher than that with marked eIF4E overexpression (more than sevenfold) (P = 0.01734, log rank test).

Marked eIF4E overexpression in gastric cancer was found to be associated with vascular invasion. The prognosis for gastric cancer patients with marked overexpression of eIF4E was worse than those with underexpression. It may serve as an additional prognostic and therapeutic factor in gastric cancer, and deserves further investigation.