紧密连接分子Occludin mRNA在胃癌中的表达和分布

目的：检测紧密连接分子Occludin在胃癌组织中的分布及表达水平,探讨其在胃癌中的表达意义及其与胃癌多药耐药性之间的关系。方法：利用原位杂交技术,对Occludin在胃癌组织中的分布和表达进行检测。结果：Occludin mRNA定位在胃腺体细胞的胞浆中,为蓝色小颗粒,呈弥漫性分布。Occludin mRNA的表达水平与组织的分化水平相关,随着胃腺癌分化程度的降低,Occludin mRNA的表达率也下降。Occludin mRNA在胃癌耐药细胞系SGC7901／VCR中的阳性信号明显高于SGC7901。胃癌与癌旁组织、胃癌与正常胃黏膜组织相比,Occludin mRNA的阳性表达率差异均有显著性（P＜0．05）。Occludin mRNA在癌旁组织（54．8％）、正常胃黏膜组织（60．9％）、高分化腺癌（56．3％）和中分化腺癌组织（28．6％）中的阳性表达率无显著差别,但高分化腺癌与低分化腺癌组织（10．0％）差异有显著性（P＜0．05）。结论：Occludin的表达水平与肿瘤的分化水平呈正相关,并可能参与了体内胃癌多药耐药现象。

In situ hybridization of tight junction molecule occludin mRNA in gastric cancer

Objective To analyze the distribution and significance of occludin mRNA expression in human gastric cancer, as well as its relationship with gastric cancer pathology and multidrug resistance (MDR) in vivo. Methods In situ hybridization (ISH) technique was used to evaluate the expression of occludin mRNA in 42 gastric carcinoma specimens obtained by surgery and 23 relatively nomal gastric mucosa obtained by gastric endoscopy. All speciments had been stored in cryostatic section. Results Occludin mRNA was found positive in the cytoplasm of gastric glandulous epithelia as blue particles with intensive stain in 14 of 42 gastric cacinomas (33.3%), 23 of 42 paracancerous gastric tissues (54.8%), 14 of 23 relatively nomal gastric tissues (60.9%), 9 of 16 well differentiated carcinomas (56.3%), 4 of 14 moderately differentiated carcinomas (28.6%), 1 of 10 poorly differentiated carcinomas (10.0%) and none of 2 mucosal carcinomas. There were significant differences in occludin mRNA positive rate between relatively normal gastric tissue and gastric cancer as well as between paracancerous gastric tissue and gastric cancer. The expression of occludin mRNA in moderately and poorly differentiated groups was gradually reduced when compared with well differentiated group, which suggests that there be a significant correlation between tumor differentiation and the expression of occludin mRNA. Furthermore, the positive signals of occludin mRNA distributed extensively in the cytoplasm of SGC7901/VCR cell, being vincristine resistant, derived from parental gastric cell line SGC7901. The positive signals of SGC7901/VCR were stronger than those of SGC7901 cells. Conclusion Occludin mRNA, being mainly located in epithelial cells and its expression correlated with tumor differentiation, may be involved in the development of multi-drug resistance in gastric cancer.