• Jesang Yu, Seung-Hyun Lee, Tae Sig Jeung, and HeeKyung Chang.
• Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul.
• Medicine (Baltimore). 2019 Jun 1; 98 (26): e16190e16190.

AbstractBiomarkers that predict tumor response before surgical treatment are necessary to help select patients for preoperative chemoradiotherapy for rectal cancer. However, no definite predictive biomarker has been established. This study explored programmed death-ligand 1 (PD-L1), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), p-signal transducer and activator of transcription 3 (p-STAT3), and death-domain associated protein as predictive biomarkers with regard to preoperative chemoradiotherapy in rectal cancer.Formalin-fixed paraffin-embedded cancer tissues from pretreatment biopsies from 31 patients who underwent preoperative chemoradiotherapy were studied. The biomarkers were evaluated by immunohistochemistry.PD-L1 positivity was found in 22.6% of 31 patients and complete response (CR) showed 33.3% and non-CR showed 18.2%. EGFR positivity was found in 71.0% of 31 patients and CR showed 88.9% and non-CR showed 73.6%. VEGF positivity was found in 83.9% of 31 patients and CR showed 88.9% and non-CR showed 81.8%. p-STAT3 positivity was found in 80.6% of 31 patients and CR showed 88.9% and non-CR showed 77.3%. On multiple logistic regression analysis, only VEGF expression was found to be a significant predictive factor for CR (P = .001). VEGF expression in pretreatment biopsies might be a predictive marker for CR after preoperative chemoradiation in rectal cancer.Although there is a restriction of small sample size, our finding suggested that this study can be foundation for a larger further study for biomarkers which can predict neoadjuvant therapy response of specimens obtained for diagnosis before surgery.

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