Preliminary proteomic analysis of radiation response markers in rectal cancer patients.

OBJECTIVE: To provide biomarkers related to the radiation response of patients to avoid unnecessary side effects on those who were not sensitive to radiotherapy. PATIENTS AND METHODS: In the present study, we compared the different four proteins (PDIA3, Vimentin, Galectin3, Dhe3) patterns in rectal tumor tissue before and after radiation therapy by using 2-D PAGE, mass spectrometry, and bioinformatics analysis. RESULTS: The protein level of Galectin3 and PDIA3 were downregulated in rectal cancer patients before and after radiotherapy (1.42 folds); while Dhe3 protein and Vimentin were upregulated (1-2 folds), and we also revealed Vimentin as its role in the negative regulation of the well-known transcription factor ATF4. CONCLUSIONS: Our study showed that four candidate proteins, including PIDA3, Galectin3, Dhe3, and Vimentin, might be the potential biomarkers in the identification of radiation response in rectal cancer.