PTGS2 and neoplasm: In this study, in ALDH3A1-silenced tumor cells, we observed a reduced expression of NFkB and COX-2, and inhibition of PGE-2 release, together with a marked subversion of the pattern of cytokine expression and release (decrease of immunosuppressive cytokines, such as IL-6 and IL-13, and increase of immunostimulating cytokines such as IL-12/23 and IFNγ), and the downregulation of the inhibitory signal PD-L1, indicating a switch to favor an active immune response.