PTEN和磷酸化Smad2在原发性肝癌中的表达

目的探讨肝癌等组织中10号染色体缺失的磷酸酶及张力蛋白同源物（PTEN）和磷酸化Smad2（P-Smad2）表达的意义。方法采用免疫组织化学技术检测肝癌组织、癌旁肝组织和非癌性肝组织中P-Smad2和PTEN的表达。结果31份肝癌组织中PTEN表达以细胞质和细胞膜明显,细胞核基本不表达；25份癌旁及13份非癌性肝组织中则以细胞核和细胞质强表达,细胞膜弱表达。PTEN在肝癌组织的表达率（64．5％）低于癌旁肝组织（96．0％）和非癌性肝组织（100．0％）,表达强度（4．19±3．31）低于癌旁肝组织（7．88±0．93）和非癌性肝组织（7．77±0．93）,差异均有统计学意义（P＜0．05）。不同病理分级的肝癌组织中PTEN的表达率差异无统计学意义（P＞0．05）,≥Ⅱ级的肝癌组织细胞质表达强度（3．07±2．87）低于＜Ⅱ级（5．80±3．12）的肝癌组织（P＜0．05）。癌旁有、无肝内血管癌栓的肝癌组织中,PTEN表达率分别为45．5％和85．7％,表达强度分别为3．00±3．46和6．28±2．37,差异均有统计学意义（P＜0．05）。PTEN在肝细胞的表达定位与病理类型呈负相关（r=0．34,P＜0．01）,与肝内血管癌栓呈负相关（r=-0．43,P＜0．05）。非癌性肝组织、癌旁肝组织和病理分级＜Ⅱ级的肝癌组织中,P-Smad2表达以细胞核和细胞质明显,≥Ⅱ级的肝癌组织中则以细胞核为主。P-Smad2在肝细胞的表达定位与病理类型呈正相关（r=0．22,P＜0．05）,P-Smad2在细胞核的表达强度。肝癌组织与癌旁肝组织的差异无统计学意义,也与肝内血管有无癌栓无关。肝癌组织中PTEN和P-Smad2表达呈负相关（r=-0．73,P＜0．01）。结论PTEN的表达、强度以及和P-Smad2的核、质转位可能与肿瘤的发展和恶化有关,二者可能存在相互作用,共同参与肝癌的发生机制。

Expressions of phosphorylated-Smad2 and PTEN in hepatocellular carcinomas and adjacent liver tissues

OBJECTIVE: To investigate the expressions of phosphorylated Smad2 (P-Smad2) and phosphatase and tensin homolog deleted on chromosome ten (PTEN) in hepatocellular carcinoma (HCC) tissues. METHODS: The expressions of P-Smad2 and PTEN were detected using Envision immunohistochemical technique in 31 cases of HCC tissues, 25 cases of HCC adjacent liver tissues and 13 cases of non-hepatocellular carcinoma tissues. RESULTS: The positive expression and staining intensity of PTEN in the cytoplasm of HCC cells (64.5%, 4.19+/-3.31) was significantly lower than those of the cells of the cancer adjacent tissues and non-cancerous tissues (96.0%, 7.88+/-0.93; 100%, 7.77+/-0.93). The staining intensity of PTEN in the cytoplasm of Edmondson pathologic grade III HCC cells was lower than those of the Edmondson grade I. The expression of PTEN was negatively correlated with intrahepatic vascular cancer thrombi (r=-0.43) and the expression of PTEN in the nuclei or cytoplasm of liver cells was negatively correlated with the liver disease progressions (r=-0.34). The positive rate and expression intensity of phosphorylated Smad2 in nuclei of HCC cells were the same as those in cancer adjacent and non-tumor liver tissues. The expression was mostly in the nucleus and cytoplasm of Edmondson grade I HCC cells, cancer adjacent liver tissue cells and non-tumor liver tissues, but its expression was only in the nuclei of Edmondson grade II and III HCC cells. The phosphorylated Smad2 expression appeared in the nuclei and in the cytoplasm of liver cells and it was positively correlated with the severity of the tumor pathology (r=0.22). Spearman correlation analysis revealed a significant inverse correlation between PTEN and phosphorylated Smad2 in HCC tissues (r=-0.73). CONCLUSIONS: The aberrant expressions of PTEN and phosphorylated Smad2 and their interaction may play an important role in the pathogenesis of hepatocellular carcinoma.