It has recently been shown that treatment of lung cancer cell lines with MEK inhibitors and histone deacetylase (HDAC) inhibitors restores responsiveness of those cells to IFN-γ treatment and induces de novo MHC-II expression.47 To determine whether blockade of MEK and HDAC pathways can induce expression of surface MHC-II in PDAC cell lines after IFN-γ treatment, we treated the IFN-γ-resistant 8988 T, FA6 and MiaPaca-2 cells with IFN-γ in the presence or absence of MEK inhibitor trametinib and/or HDAC inhibitor TSA for 48 h. This evidence concerns the gene HDAC9 and lung cancer.