ALDH1A1 and colorectal carcinoma: Although ALDH1A1 might thus be involved in CRC, its relation to features of poor prognosis in CRC, including a poorly differentiated histology [15, 16], ‘right-sidedness’ of the primary tumor [17], presence of metastases [3, 4] and a mesenchymal (MES)-like phenotype [18] is not clear.