ALDH1A1 and neoplasm: The tumor tissue derived from the PANC-1 xenografts was further analyzed by immunohistochemistry, demonstrating that 3BrP, but not gemcitabine, strongly reduced the expression of the stem cell markers ALDH1, CD44, CD133, Sox2, and CxCR4 and the proliferation marker Ki67, whereas the apoptosis marker “cleaved fragment of active caspase 3” was strongly enhanced (Fig. 5F, Fig. S3).