Clinical significance of expression of inositol polyphosphate-4-phosphatase type II and Akt in esophageal squamous cell carcinoma

Abstract

Objective To investigate the expression of inositol polyphosphate-4-phosphatase type Ⅱ (INPP4B) and Akt in esophageal squamous cell carcinoma (ESCC) and to explore their correlation with clinicopathologic factors. Methods The expression of INPP4B mRNA in 32 ESCC tissues was detected by quantitative real-time PCR (qRT-PCR). The relationship between INPP4B expression and clinical and pathological characteristics was then analyzed. Immunohistochemistry was performed to detect the expression of INPP4B and Akt proteins in 70 specimens of ESCC and 20 specimens of normal esophageal tissues. The relationship of their expression with clinicopathologic factors was analyzed. Results INPP4B mRNA expression was significantly higher in 32 ESCC tissues than in adjacent normal tissues (P 0.05). In 70 ESCC tissues and 20 normal esophageal tissues, the rates of INPP4B and Akt expression were significantly higher in ESCC tissue than in normal esophageal tissue (INPP4B: 67.1% vs 40.0%, P<0.05; Akt: 72.8% vs 25.0%, P<0.05). INPP4B protein expression was not correlated with tumor differentiation, lymph node metastasis, or TNM stage. Akt expression was correlated with tumor size, tumor differentiation, lymph node metastasis, and TNM stage. INPP4B expression was positively correlated with Akt expression (r = 0.531, P = 0.000) in ESCC. Conclusion INPP4B expression is up-regulated in ESCC at both the mRNA and protein levels. INPP4B may act as an oncogene through promoting the activation of Akt in ESCC. INPP4B may be a new therapeutic target for ESCC. Key words: Esophageal carcinoma; Inositol polyphosphate-4-phosphatase type Ⅱ; Quantitative real-time PCR; Immunohistochemistry; Akt