Abstract: Objective: To establish an EC 9706 esophageal cancer cell line that overexpresses the point mutation and deletion repai r variants of DNA polymerase β (pol β) in esophageal cancer and to investigate the changes in the biological characteristics of the cell line. Methods:The point mutation and deletion repair vari-ants of DNA polymerase β were ampl i fied from recombinant expression plasmid pcDNA3.1-pol β using PCR. The primers were designed according to the cDNA sequence of DNA polymerase β (Genbank). The point mu-tation and deletion repai r variants of the DNA polymerase β gene were cloned into the pEGFP-N3 vector. The recombinants were then transfected into the EC 9706cell line using lipofectamine. The localization of proteins encoded by the2 variants was detected by inverted fluorescent microscopy. The growth curves were drawn using results from MTT assay and the percentage of cells in each phase of the cell cycle was detected by flow cytometry. Results: The sequences of the DNA polymerase β variants were correct and they were successful ly transfected into the EC 9706 cel l l ine. The point mutation repai r DNA polymerase β protein was mostly inside the nucleus, but the deletion repair DNA polymerase β protein could be seen in the whole cel l . The growth of EC9706 cells transfected with the deletion repair variant was obviously slower than that of the controls ( P<0.05). The number of cells in S phase was 36.72% in the cells transfected with point mutation and deletion repai r DNA polymerase β, and 26.82% in the cel ls transfected wi th the point mutation repair DNA polymerase β alone (P<0.05). Conclusion:An EC 9706 cell line overexpressing the point mutation or deletion repair variants of DNA polymerase β has been successful ly establ ished. The biological characteristics of the cel l l ine changed after transfection wi th the DNA polymerase β variants. This study warrants further investigation into the pathogenesis of esophageal cancer.