DNA polymerase beta overexpression correlates with poor prognosis in esophageal cancer patients

Gene of DNA polymerase beta (polβ) plays an important role in base excision repair, DNA replication and translesion synthesis. This study aims to investigate the expression and prognostic significance of DNA polβ in esophageal cancer. DNA polβ expression was analyzed using real-time quantitative PCR (RT-qPCR) and immunohistochemical staining on tissue samples from a consecutive series of 114 esophageal squamous carcinoma patients who underwent resections between 2002 and 2006. Polβ expression was investigated on its correlation to clinico-pathological factors and survival. RT-qPCR results showed higher expression of DNA polβ mRNA in tumor tissue than in its matched adjacent non-tumor tissue sample, different expression of DNA polβ mRNA was noticed with significance between tumors with and without lymph node metastasis. Immunohistochemistry staining results indicated the polβ strong-positive rate was 44.73% (51/114) in tumor tissue samples and 0.00% in matched adjacent non-tumor tissue samples, with significant difference. Kaplan-Meier survival curves revealed that high expression of pol? was associated with tumor metastasis and poor prognosis in esophageal cancer patients. Our data suggests that polβ plays an important role in tumor progression and that high polβ expression predicts an unfavorable prognosis in esophageal squamous carcinoma patients.