On the other hand, a lack of correlation between ALDH1 expression and grade of differentiation or histopathologic pattern in malignant salivary gland tumors indicates that cancer stem cells might not have a role in the morphogenesis of salivary gland tumors, or that other isoforms of ALDH or other markers of cancer stem cells are effective in this regard. This evidence concerns the gene ALDH1A1 and cancer.