Effect of Ptpn1/2 knockout on the transcriptome of unstimulated or IFN-beta stimulated B16-OVA cells

Immune evasion by cancer cells remains a major barrier to the success of immune checkpoint blockade (ICB). Here, we identify the phosphatases PTPN1 and PTPN2 as cooperative regulators of tumor immune resistance. Dual genetic ablation or pharmacologic inhibition of PTPN1/2 enhances Type I and II interferon signaling, MHC-I and CXCL9 expression, and sensitizes tumor cells to cytotoxic T lymphocyte–mediated killing. The small-molecule inhibitor KQ791 phenocopies these effects and synergizes with anti-PD1 therapy to suppress tumor growth in murine models, including immunotherapy-refractory cancers. Mechanistically, PTPN1/2 loss augments STAT1/3/5 signaling and primes cancer cells for immunogenic cell death via IFNγ/TNFα-induced pathways. Moreover, PTPN1/2 inhibition enhances antigen release and cross-presentation, promoting robust antigen-specific CD8⁺ T cell responses. These findings highlight PTPN1&2 as essential mediators of cancer immune evasion and support their inhibition as a strategy to broaden the effectiveness of immune checkpoint blockade in solid tumors.