Evaluation Of Potential Tumor Markers That May Predict Neoadjuvant Treatment Efficiency In Rectal Cancer

Objectives: The recurrence of rectal cancer or its resistance to neoadjuvant treatment develops due to the adaptation to hypoxia, apoptosis or autophagy. Survivin, one of the inhibitors of apoptosis; Beclin 1, which is a positive regulator in the autophagy pathway; and hypoxia-inducible factor-1 alpha (HIF-1 alpha) and carbonic anhydrase-9 (CA9), which are associated with tumor tissue hypoxia, may be related to resistance to treatment. Our aim was to evaluate the potential tumor markers that may help to monitor the response to neoadjuvant treatment in locally advanced rectal cancer (RC).Methods: Twenty-five patients with locally advanced RC were included in the study. Gene expression and protein levels of Beclin 1, Survivin, HIF-1 alpha, and CA9 were analyzed in fresh tissue specimens and blood samples. The relationships of these markers to tumor staging and regression grade were evaluated.Results: Higher blood CA9 gene expression levels and lower blood HIF-1 alpha protein levels were found in the response group according to tumor regression grade. After neoadjuvant treatment, tissue Beclin 1 and blood Survivin gene expressions and tissue CA9, blood Beclin 1 and blood HIF-1 alpha protein levels decreased significantly.Conclusion: Beclin 1, Survivin, HIF-1 alpha ve CA9 may help to predict the effects of the applied treatment approach.