Expression And Prognostic Significance Of PI3K In Esophageal Squamous Cell Carcinoma

Objective: To explore the express of phosphoinositide 3-kinase (PI3K) in esophageal squamous cell carcinoma (ESCC) and the correlation between PI3K and clinicopathologic features, hoping to provide a new theoretic basis for clinical diagnosis, treatment and predicting prognosis.Methods: The expression of PI3K was detected by S-P immunohistochemical (IHC) staining and reverse transcriptase polymerase chain reaction (RT- PCR) in ESCC. All data were analysized by SPSS 13.0 for windows.Results: 1 The immunohistochemical staining results: 1.1 In 91 ESCC, the positive expression rate of PI3K was 86.31% (79/91), while that was of significantly higher expression in esophageal mucosa 10.00% (1/10) (P<0.001);1.2 The positive rates of expression of PI3K in ESCC of grade I,II andⅢwere 50.00% (3/6), 90.38% (47/52) and 87.88% (29/33), respectively. The difference was significant among them (P<0.05). Spearman correlation analysis indicated that the poor differentiation of ESCC , the higher protein level of PI3K expression (rs=0.351,P<0.05);1.3 The positive rates of expression of PI3K in ESCC of invasive depth were submucosa 37.50%, muscular layer 90.00% and fibrous layer 92.06%, respectively. The difference was significant among them (P<0.05). Spearman correlation analysis indicated that the deeper invasive depth of ESCC, the higher protein level of PI3K expression (rs=0.210,P<0.05);1.4 The positive rates of expression of PI3K in ESCC of clinical stage were 0～Ⅰstage 37.50% (3/8),ⅡA stage 90.60% (48/52),ⅡB stage 60.00% (3/5),Ⅲstage 80.00% (4/5) andⅣstage 100.00% (21/21), respectively. The difference was significant among them (P<0.05). Spearman correlation analysis indicated that the higher clinical stage of ESCC, the higher protein level of PI3K expression (rs=0.240,P<0.05);1.5 PI3K protein expression was not correlated with age, gender and metastasis of lymph node (P>0.05).2 The RT-PCR results demonstrate: 2.1 The PI3K mRNA expression was detected in 25 of 30 ESCC and 8 of 30 esophageal mucosa tissues. The level of PI3K mRNA expression in ESCC was 0.675±0.029, while that was significant higher than that in esophageal mucosa 0.349±0.073 (P<0.001);2.2 PI3K mRNA relative expression level in moderate and low-differentiated group was 0.680±0.024, while that was of significantly lower expression in well-differentiated 0.622±0.014 (P<0.05);2.3 PI3K mRNA relative expression level in superficial muscle was 0.658±0.032, while that was of significantly higher expression in fibrous layer 0.684±0.023 (P<0.05);2.4 Different clinical stages of the relative PI3K mRNA expression wereⅠ-Ⅱperiod of 0.665±0.032,Ⅲ-Ⅳperiod of 0.689±0.016. Difference was statistically significant after statistical analysis (P<0.05);2.5 PI3K mRNA expression was not correlated with age, gender and lymph node metastasis (P>0.05).3 The expression of protein and prognosis: In 91 ESCC, by Kaplan-Meier analysis following factors were observed to be significantly associated with prognosis: PI3K expression, the degrees of differentiation, invasive depth, lymph node metastasis, clinical stage, tumor embolus, stump invaded (all P<0.05). 5-year survival rate of patients with positive expression of PI3K (41.70%) was lower than those negative expression (83.30%). On multivariate analysis, following variables had significant effect on prognosis: clinical stage, invasive depth and stump invaded (all P<0.05). PI3K was not the independent prognosis indicator by multivariate analysis of Cox model (χ2=1.235,P=0.266). It was demonstrate the expression of PI3K influenced the prognostic of ESCC, but it was not the independent prognosis indicator. The positive expression of PI3K as a reference index of ESCC indicated poor prognosis.Conclusion:1 The expression levels of PI3K protein and mRNA in ESCC tissues were significantly increased than in esophageal mucosa. There was appositive relationship between P13K expression and the degrees of differentiation, invasive depth and clinical stage. PI3K had the role in the occurrence and development of ESCC.2 PI3K protein and mRNA expression were not correlated with age, gender and metastasis of lymph node (P>0.05).3 PI3K was not the independent prognosis indicator by multivariate analysis of Cox model. The enhanced expression of PI3K as a reference index of ESCC indicated poor prognosis.