ALDH1A1 and neoplasm: The panel of different PCa aggressiveness- and progression-related proteins was assessed before in tumor cells of individual tumor samples of the examined patients: Ki-67, apoptosis marker (ApopTag), cytokeratins (CK5/6, CK14, CK8/18, CK19), vimentin, E- and N-cadherin, aldehyde dehydrogenase 1 (ALDH1), epidermal growth factor receptor (EGFR), epithelial cell adhesion molecule (EpCAM), B-cell lymphoma-2 apoptosis regulator (Bcl-2), and lysyl oxidase homolog 2 (Loxl-2) [16,17].