The Expression Of GASC1in Patients With Esophageal Squmous Cell Cancer And Its Clinical Significance

Objective: To detect the expression of gene amplified in squamous cellcarcinoma1(GASC1)in esophageal squamous cell carcinoma(ESCC) viaimmunohistochemistry、Western blotting and RT-PCR, and investigate its relationshipwith clinical pathological characteristics and prognosis.Methods:82primary ESCC tumor tissue specimens and adjacent normal mucosawere obtained in the First Affiliated Hosptial, Henan University of Science andTechnology. They were diagnosed and surgically treated from January2011toDecember2011.40normal esophageal mucosa as a negative control. The expressionof GASC1at the mRNA and protein level was studied by RT-PCR and westernblotting, respectively. GASC1protein levels in ESCC and normal esophageal mucosatissue were examined via immunohistochemistry, and were compared with specificclinicopathological types of the patients and tissue specimens. patients survival withdifferent GASC1expression were also analyzed.Results:1. In the immunohistochemistry of82ESCC,51.2%of the cases were GASC1positive and48.8%negative. High expression of GASC1in ESCC patients wassignificant difference with the degree of differentiation, infiltration depth, lymph nodemetastasis and clinical stage (χ2, P=0.021, P=0.037, P=0.004, P=0.011). Furthermore,the positive rate of GASC1in esophageal cancer, adjacent normal mucosa and normalesophageal mucosa tissues were51.2%,45.1%and52.5%respectively. There was nosignificant correlation among esophagea cancer, adjacent normal mucosa and normalesophageal mucosa (P=0.532and P=0.524). however, with the results of adjacentnormal mucosa as standard, the consistency between esophageal cancer and adjacentnormal mucosa is Kappa=0.538. Indicate that in the same patient there has consistencybetween esophageal cancer and adjacent normal mucosa.2. Western blotting showed that there was no significant difference in GASC1 mRNA expression between esophageal cancer and adjacent normal mucosa（P=0.973）. The results aslo revealed the distribution of GASC1protein expressionwas significantly lower in well differentiated esophageal cancer compared withmoderate/poor differentiated esophageal cancer (P=0.017). Furthermore, in order toverify the above results, Western blotting analyses were conducted to determine thelevels of GASC1protein in five ESC cell lines. The results revealed that GASC1expression was significantly higher in those cell lines representing poor differentiatedesophageal cancer(KYSE150、KYSE70) compared with the cell lines representingwell and medium differentiated esophageal cancers(KYSE140、KYSE30、 EC9706).The result was consistent with above.3. RT-PCR showed that there was no significant difference in GASC1mRNAexpression between esophageal cancer and adjacent normal mucosa(P=0.620). RT-PCRresults aslo revealed the distribution of GASC1mRNA expression was significantlylower in well differentiated esophageal cancer compared with moderate/poordifferentiated esophageal cancer (P=0.006). Furthermore, in order to verify the aboveresults, RT-PCR analyses were conducted to determine the levels of GASC1mRNA infive ESC cell lines. The results revealed that GASC1expression was significantlyhigher in those cell lines representing poor differentiated esophagealcancer(KYSE150、KYSE70) compared with the cell lines representing well andmedium differentiated esophageal cancers(KYSE140、 KYSE30、 EC9706). Theresult was consistent with above.4. Correlation analysis was carried out on the immunohistochemical、Westernblotting and RT-PCR result. The results show that they are significantly positivecorrelated. This indicate that GASC1protein levels were in line with mRNAexpression.5. We follow up82patients with esophageal cancer. The Kaplan-Meier survivalanalysis indicated a tendency that positive expression of nucleus GASC1wasassociated with poor survival of ESCC patients(P=0.040), with two-year survival rateof65.8%, as compared to86.4%for patients with GASC1-negative expression.Conclusions:1. High expression of GASC1in ESCC patients was significant difference inmore aggressive pathologic classification (T3stage, moderate/poor differentiation,nodal positive and clinical stage III). Our study provides evidence that GASC1may associated with esophageal malignant phenotype and invasive ability.2. There no significant correlation among esophagea cancer, adjacent normalmucosa and normal esophageal mucosa. Indicated that GASC1has no correlation withoccurrence of tumor and may be related to progression.3. The survival analysis showed a tendency that positive expression of nucleusGASC1was associated with poor survival of ESCC patients, indicated GASC1isassociated with patients poor prognosis and may be a prognostic marker of ESCCpatients.