POU5F1 and pancreatic neoplasm: Interestingly, strong downregulation of expressions of the reprogramming factors such as Sox-2, Nanog-1 but not Oct-4 were found after carbon ion beam combined with gemcitabine compared to that of carbon ion and X-ray alone or X-ray combined with gemcitabine, indicating that carbon ion beam combined with chemotherapy may have more potential to regress pancreatic cancer cell stemness.