Detection And Diagnostic Significance Of Stem Cell Markers Oct4,Nanog, And ABCG2 In Human Gastric Cancer

Objective To detect the expression of stem cell markers such as Oct4,Nanog,and ABCG2 in paired gastric cancer(GC) and correspoding, non-cancerous tissues and to explore whether their expression are correlated with the clinicopathological parameters of human GC and the possibility that they could be served as novel molecular markers for human GC.Methods Tumor cell lines(SGC7901,SW480) were cultured.The primary tumor tissues and matching,adjacent non-cancerous tissues from 62 GC patients were collected.20 biopsy specimens of atrophic gastritis and gastric ulcer individually were collected as controls by gastrointestinal endoscopic examination.The expression of Oct4,Nanog, and ABCG2 in the gastric cancer and matching,adjacent non-cancerous tissues and Oct4 expression in atrophic gastritis and gastric ulcer tissues were examined by reverse transcription-PCR(RT-PCR) and real-time PCR.To detect Oct4 and ABCG2 expression in the paired gastric cancer and non-cancerous tissues at the protein level,Western blot and immunohistochemistry(IHC) were employed.Correlation analyses were conducted to assess the relationship between Oct4,Nanog,and ABCG2 expression and clinicopathological parameters.Results RT-PCR results showed that the positive rates of Oct4, Nanog,and ABCG2 expression in gastric tumor tissues were 67.7%(42/62),58.1%(36/62),61.2%(38/62),which were significantly higher than those in the matching,adjacent non-cancerous tissues: 6.5%(4/62),9.7%(6/62),11.3%(7/62),(P<0.01),respectively.Of the 20 cases with atrophic gastritis,3 were positive for Oct4 expression(15.0%) and 10.0%(2/20) was also positive in the samples of gastric ulcer,both of which were statistically lower than that in the gastric cancer tissues group(P<0.01).Real-time PCR results revealed that relative level of Oct4 expression in tumor tissues was significantly higher than those in the corresponding,adjacent non-cancerous tissues,atrophic gastritises, and gastric ulcers(P<0.05).Nanog expression in tumor tissues was also significantly higher than that in the corresponding,adjacent non-cancerous tissues(P<0.05).Oct4 and ABCG2 expresssion at the translational levels were verified by western blot and immunohistochemistry.Oct4,Nanog,and ABCG2 expression in gastric cancer tissues correlated with their differentiation status,but not with patient age or gender,tumor size,TNM stage,depth of invasion,or the presence of lymph node metastasis.Conclusions Oct4,Nanog,and ABCG2 expression in gastric cancer tissues were associated with the differentiation status of GC.They may serve as novel diagnostic markers for human GC.