APPLICATION OF TWO-DIMENSIONAL ELECTROPHORESIS AND NIH 3T3 CELL TRANSFECTION ASSAY IN THE STUDY OF TUMOR-AS SOCIATED PROTEINS AND GENOMIC DNA TUMOROGENICITY IN MALIGNANT HUMAN ESOPHAGEAL SPECIMENS

Total protein and DNA extracted from histologically diagnosed normal nonmalignant and esophageal tumor tissues were used for analysis of polypeptides pattern by two-dimensional gel electrophoresis and DNA transforming activity in NIH 3T3 cell transfection assay, respectively. In comparison to normal tissues, eight polypeptides underwent down-regulation or disappeared, while seven polypeptides were subjected to up-regulation or appeared for the first time in tumor tissues. We suggest that the first eight polypeptides are necessary for maintenance of normal phenotype and the other seven polypeptides are involved in the development of malignant phenotype. However, results obtained from NIH 3T3 cell transfection with esophageal tumorous DNA showed that such DNAs lack transforming efficiency. These data may agree with the published reports about the absence of activated transforming oncogenes such as the ras family in esophageal cancer specimens