Detection Of ERp29Expression And Its Clinical Significance In Gastric Cancer By Tissue Microarray

Objective：70differentially expressed proteins between gastric carcinoma tissues and adjacent normal mucosal tissues were identified using two-dimensional electrophoresis and mass spectrometry identification in our previous study. Altogether,43types of proteins were down-expressed in gastric carcinoma, while the other27types of proteins were over-expressed, respectively. ERp29protein, which was preliminary proved down-expressed in gastric carcinoma, was selected for this study. We aimed to further explored the relationship between expression of ERp29in gastric carcinoma and clinicopathological parameters and their clinical significance, in addition, to construct the ERp29over-expressed vector, which would help to further study of this protein.Methods：In the first part of this study, we preliminary investigated the expression of ERp29in8gastric carcinoma tissues and the adjacent normal mucosal tissues by western-blot and RT-PCR in protein and mRNA level, respectively. Then we detected the expression of ERp29in170gastric carcinoma tissues and the adjacent normal mucosal tissues by tissue microarray combined with immunohistochemistry, and analyzed the relationship between ERp29expression and the clinicopathological parameters, which including patients’ age, gender, depth of invasion, serosal invasion, pathological stage, lymph node metastasis, differentiation, vascular invasion, histological types, size, distant metastasis, peritoneal invasion.In the second part, we cloned the ERp29gene sequence into pcDNA3.1/Hygro(+) plasmid to construct ERp29-pcDNA3.1recombined plasmid, and transfected the vector into gastric cancer cells SGC7901and AGS after conformed by restriction endonuclease analysis and sequencing, then we detected the ERp29expression level by western-blot.Results：1.Western-blot：Compared with the adjacent normal mucosal tissues, the ERp29protein level was lower in gastric carcinoma tissues in7cases, whereas, ERp29was up-expressed in gastric carcinoma tissue in another one case, the difference was statistically significant（P=0.032）.2.RT-PCR: Compared with the adjacent normal mucosal tissues, the ERp29mRNA level was significantly lower in gastric carcinoma tissues in the all8cases, the difference was statistically significant（P＜0.05）.3. Tissue micro-array and immunohistochemistry(1) Compared with the adjacent normal mucosal tissues, the expression of ERp29in the gastric carcinoma was significantly lower, the positive expression rate was47.1%and85.3%, respectively（P=0.001）.(2) Statistical analysis revealed that the expression of ERp29was closely related to patients’ gender, lymph node metastasis, TNM stag（eP<0.05）,but no related to patients’ age, depth of invasion, serosal invasion, differentiation, vascular invasion, perineural invasion, histological types, size, peritoneal invasion and distant metastasis（P>0.05）.(3) The positive expression rate of ERp29in male and female was53.6%and28.9%with a statistically significant（P=0.004）, and there was a negative correlation with TNM stage, lymph node metastasis, number of lymph node metastasis（P=0.006,0.027,0.002）.4. The expression of ERp29was obviously higher in the gastric carcinoma cells after infected by the recombinant plasmid.Conclusions：1. The ERp29expression was down-expressed in gastric carcinoma.2. ERp29was a potential tumor suppressor factor closely related to lymph node metastasis and TNM stages and played an important role in the occurrence and development of gastric carcinoma.3. ERp29over-expressed vector was constructed successfully.