Due to the poor tumor-forming ability of MIA PaCa-2 cells in in vivo experiments, PANC-1 cells with the second highest expression of SOX21-AS1 were selected for loss-of-function assays, whereas CFPAC-1 cells with the lowest expression were selected for gain-of-function assays, based on the RT-qPCR results of PDAC cells. This evidence concerns the gene SOX21 and neoplasm.