Preliminary Study On The Relationship Between EGFR/STAT1 Signaling Pathway And Esophageal Cancer

Objective: To study the expression and activation of STAT1 and its related signaling factor ERK in esophageal cancer of Chaoshan region and investigate the possible function of EGFR/STAT1 signaling pathway in the occurrence and development of esophageal cancer, which will provide target selections base for the treatment of esophageal cancer with EGFR inhibitors.Materials and methods:(l) The expression and distribution of EGFR, STAT1, pSTATl in 38 cases of esophageal cancer and 10 cases of histologicaly normal esophageal tissue's paraffin slices were tested by immunohistochemistry method, meanwhile the expression and distribution of pERK in 3 cases of the above mentioned cancer tissue and 10 cases of normal tissue was tested. (2) The expression of EGFR, STAT1, pSTATl, pERK and ERK in 15 cases of fresh esophageal cancer and the corresponding 13 cases of precancer tissue and 14 cases of histologicaly normal tissue were tested by Western-blot. Results:(l) immunohistochemistry :(1) EGFR expression in histologicaly normal tissue and esophageal cancer : EGFR wasn't expressed in the 10 cases of histologicaly normal tissue;of the 38 cases of cancer tissue, EGFR expression was detected in 18 (47%) cases. Positivesignals were mainly observed throughout the membrane and cytoplasm of cancer cells, and furthermore, some positive signals were also found in the nuclei.(2) STAT1 expression in histologicaly normal tissue and esophageal cancer: STAT1 was expressed in all the cases of cancer tissue and corresponding histologicaly normal tissue. Positive signals were detected in the cytoplasm and nuclei of cancer cells and histologicaly normal esophageal epithelial cells. Signals in nuclei were stronger.(3)pSTATl expression in histologicaly normal tissue and esophageal cancer: pSTATl wasn't expressed in either histologicaly normal tissue or cancer tissue.() pERK expression in histologicaly normal tissue and esophageal cancer: pERK was expressed in all the 10 cases of histologicaly normal tissue,in wich positive signals were detected mainly in the nuclei of the esophageal epithelial cells ,and stronger signals were found in the basal cells;Of the 3 cases of cancer tissue ,one case shows that pERK was expressed in most cancer cells,another two cases show that it was expressed only in several cells,and the positive signals were mainly found in the cancer cells' nuclei. (2) Western-blot:(1) EGFR expression in esophageal cancer tissue, corresponding precancer tissue and histologicaly normal tissue: EGFR was expressed in all the tissues. EGFR expression pattern in normal tissue, precancer tissue and cancer tissue showed an increasing trend, and its expression in cancer tissue was significantly higher than that in the histologicaly normal tissue.(2) STATl expression in esophageal cancer tissue, corresponding precancer tissue and histologicaly normal tissue: STATl was positive in all the tissues.(3) pSTATl expression in esophageal cancer tissue, corresponding precancer tissue and histologicaly normal tissue: pSTATl was faintly expressed in 10/42 cases including 3/15(20%) cases of cancer tissue, 3/13(23%)cases of precancer tissue and 4/14 cases (29%) of histologicaly normal tissue. There's no consistent performance for the expression of pSTATl in these three kinds of tissues:of one patient, if pSTATl was expressed in the cancer tissue, it does not mean it was also expressed in the precancer tissue and/or normal tissue.(4) pERK expression in esophageal cancer tissue, corresponding precancer tissue and histologicaly normal tissue: pERK expression in 10/14 (71%) cases of esophageal cancer tissue was lower than that in corresponding histologicaly normal tissue, and pERK expression pattern in the histologicaly normal tissue,precancer tissue and cancer tissue showed a decrease trend, furthermore, its expression in histologicaly normal tissue was significantly higher than that in cancer tissue(P<0.05).(5) ERK...