['To assess the expression pattern of aldehyde dehydrogenase 1A1 (ALDH1A1) in the normal-adenoma-primary carcinoma-liver metastasis sequence, and investigate its association with clinicopathological features and outcomes.', 'Immunohistochemistry for ALDH1A1 was performed on two cohorts. One used tissue microarrays (TMAs) of 395 primary colorectal carcinomas, and the other used whole-tissue sections from 217 adenomas, 265 primary carcinomas, and 72 liver metastatic carcinomas. Both the epithelial and stromal expression of ALDH1A1 were evaluated. Both cytoplasmic and nuclear expression were assessed in epithelial cells.', 'In the TMA and whole-tissue cohorts, univariate analysis indicated that the cytoplasmic expression of ALDH1A1 cannot be considered as a prognosis marker of CRCs. In the whole-tissue cohort, nuclear expression was found in a small subgroup of CRC patients. Here, both univariate and multivariate analysis showed that nuclear expression was significantly associated with longer disease-specific survival. In addition, we found that nuclear expression in low-grade adenoma was predominant over high-grade adenoma, primary CRC and the correpsonding liver metastasis.'] Is nuclear aldehyde dehydrogenase 1A1 ( ALDH1A1 ) expression a favorable prognostic indicator in colorectal carcinoma?