Specifically, cytosolic isoforms ALDH1A1, ALDH1A2 and ALDH1A3 play crucial roles in cell signaling via the oxidation of retinaldehyde to retinoic acid, which modulates a broad spectrum of biological processes including cell proliferation, differentiation, cell cycle arrest and apoptosis [28], processes that have been related to tumor initiation and progression. This evidence concerns the gene ALDH1A2 and neoplasm.