Clinical significance of the expression of eukaryotic initiation factor 4 E and mammalian target of rapamycin in esophageal squamous carcinoma tissues

Abstract

To explore the clinical significance of eukaryotic initiation factor 4 E (eIF4E) and mammalian target of rapamycin (mTOR) expressions in esophageal squamous carcinoma tissues. Clinicopathological data and paraffin samples of resected tumor tissue from 148 patients with esophageal squamous carcinoma undergoing resection in our department between January 2010 and December 2012 were collected retrospectively. Expressions of eIF4E and mTOR were detected in above carcinoma tissues, counterpart para-carcinoma tissues (1 cm distance to carcinoma) and normal tissues (5 cm distance to carcinoma) with Western blot and immunohistochemistry. Their relevance with clinicopathological features was analyzed. Expression of mTOR located mainly in cytoplasm and elF4E mainly in cellular membrane, presenting as yellow grains. These two markers showed strong expression in carcinoma tissues and weak or none in para-carcinoma tissues. In esophageal squamous carcinoma tissues, counterpart para-carcinoma tissues and normal tissues, mTOR protein expression was 85.8% (127/148), 35.1% (52/148) and 3.4% (5/148), eIF4E protein expression was 93.9% (139/148), 35.1% (52/148) and 12.8% (19/148), with a downtrend respectively (all P<0.05). Expressions of mTOR and eIF4E were associated with tumor invasion depth and lymphatic metastasis (all P<0.05), while mTOR expression was associated with differentiation degree (P=0.003), but eIF4E expression was not. Both expressions were not associated with gender, age, and tumor size (all P>0.05). Expressions of eIF4E and mTOR are up-regulated in esophageal squamous carcinoma tissues, which may be associated with tumor malignance and lymphatic metastasis of esophageal squamous carcinoma. Combined detection of two markers may be helpful to predict the tumor malignance and the prognosis of patients.