Prognostic impact of changes in base excision repair machinery in sporadic colorectal cancer

Abstract

Objectiveto evaluate the prognostic value of base excision repair proteins in sporadic colorectal cancer. MethodsPre-treatment tumor samples from 72 patients with sporadic colorectal adenocarcinoma were assessed for APC, MPG, Polβ, XRCC1 and Fen1 expression by immunohistochemistry. The associations of molecular data were analyzed in relation to clinical features and TNM staging as a prognosis predictor and disease-free survival. ResultsHigher levels of MPG, Polβ and XRCC1, but not Fen1, were associated with unfavorable pathological outcomes, such as poor cellular differentiation, advanced TNM stages, presence of lymphatic and perineural invasions and metastatic lymph nodes. MPG and Polβ overexpression were associated with right-sided CRC. However, only MPG high expression is associated with shorter disease-free survival in CRC patients. ConclusionsOur results suggest that increased expression of MPG, Polβ and XRCC1 are more likely to evolve to poor pathological outcomes, but only the elevated expression of MPG protein predicts recurrence. The BER proteins appear to be suitable candidates to refine the TNM current staging of colorectal cancer.