The ratio of FABP5/CRABP2 was previously demonstrated to be associated with ATRA resistance in gliomas, with prognostic behavior in pancreatic ductal adenocarcinoma cell lines, with activation of PPAR instead of RAR in a breast cancer mouse model and with tumor grade and prognosis in breast cancer [63, 67–69]. Here, CRABP2 is linked to pancreatic ductal adenocarcinoma.