N-terminal truncated carboxypeptidase E expression is associated with poor prognosis of lung adenocarcinoma

Lung cancer is a malignant tumor with high morbidity and mortality rates. To date, no suitable molecular diagnostic tool to predict disease recurrence and metastasis has been identified. The current study aimed to evaluate the potential of N-terminal truncated carboxypeptidase E (CPE Delta N) to predict the recurrence and metastasis of lung adenocarcinoma. Western blotting revealed the co-expression of CPE and CPE Delta N in the surgically collected pathological and pericarcinoma tissues tissues of 62.1% (59/95) lung adenocarcinoma patients. The full length CPE protein was predominantly expressed in pericarcinoma tissues and CPE Delta N expression was identified in the pericarcinoma normal tissues of only 5.26% (5/95) patients. The 3-year postoperative recurrence and metastasis rates were significantly higher in patients with positive CPE Delta N expression than in patients with negative CPE Delta N expression (P=0.009). Furthermore, the overall survival rate of patients with predominant nuclear CPE expression was lower than that of patients with predominant cytoplasmic CPE expression (46.3 vs. 64.7%); however, no statistically significant difference was identified (P=0.125). Thus, the results of the current study indicated that CPE Delta N may present a novel molecular biomarker for predicting recurrence and metastasis of lung adenocarcinoma, which may aid with stratifying patients by risk and thus, may facilitate individualized therapy.