The innate sensor ZBP1-IRF3 axis regulates cell proliferation in multiple myeloma

Multiple myeloma is a malignancy of plasma cells initiated and driven by primary and secondary genetic events. However, myeloma plasma cell survival and proliferation might be sustained by non-genetic drivers. Z-DNA-binding protein 1 (ZBP1; also known as DAI) is an interferon-inducible, Z-nucleic acid sensor that triggers RIPK3-MLKL-mediated necroptosis in mice. ZBP1 also interacts with TBK1 and the transcription factor IRF3 but the function of this interaction is unclear, and the role of the ZBP1-IRF3 axis in cancer is not known. Here we show that ZBP1 is selectively expressed in late B-cell development in both human and murine cells and it is required for optimal T-cell-dependent humoral immune responses. In myeloma plasma cells, the interaction of constitutively expressed ZBP1 with TBK1 and IRF3 results in IRF3 phosphorylation. IRF3 directly binds and activates cell cycle genes, in part through co-operation with the plasma cell lineage-defining transcription factor IRF4, thereby promoting myeloma cell proliferation. This generates a novel, potentially therapeutically targetable and relatively selective myeloma cell addiction to the ZBP1-IRF3 axis. Our data also show a noncanonical function of constitutive ZBP1 in human cells and expand our knowledge of the role of cellular immune sensors in cancer biology

PD-L1 testing in advanced stage lung cancer using cytology samples: Suitability and reporting issues. Comparison between two tertiary referral centers

Background: Lung cancer is the most common cause of cancer-related death worldwide and unfortunately up to 80% of patients amongst newly diagnosed are inoperable therefore the cytological sample is often the only material available for diagnosis and assessment of molecular characteristics driving the treatment. Recently immunotherapy has shown promising results in tumors expressing Program Death Ligand 1 (PD-L1). The expression of PDL1 can routinely be detected by immunohistochemistry. However, the presence of several antibodies with different cut-off and the expression of this marker by normal immune cells are generating confusion in interpretation and the need for harmonization amongst pathologists.Materials and methods: We assessed the suitability of 74 consecutive cell blocks from cytology samples for PDL1 testing and evaluate the concordance between two different antibodies (Ventana assay SP263 and Dako 223C pharmDx assay) and amongst different pathologists from two different tertiary referral center for thoracic pathology. The degree of agreement was measured by Fleiss K statistic (FKS) for categorical scores after dichotomization based on specified cutoffs. A review of discordant cases was also performed.Results: Review of the slides stained with both antibodies showed substantial agreement within our department and moderate agreement with results from the other institution. Overall less than 10% of cases were deemed inadequate. Discordant cases showed a decreased amount of tumor cells, therefore, tumor heterogeneity could be responsible for the variation in the reading.&nbsp;Conclusions: Our results show overall concordance between the two antibodies and the suitability of cytology material for PDL-1 testing.</p

Programmed cell death ligands expression in phaeochromocytomas and paragangliomas: Relationship with the hypoxic response, immune evasion and malignant behavior

ABSTRACT The hypoxic response underlies the pathogenesis and malignant behavior of PCC/PGL. Regulation of PD-1 receptor-ligand signaling, a therapeutically actionable driver of the anti-tumor immune response, is a hypoxic-driven trait across malignancies. We evaluated the prognostic role of PD ligands in association with biomarkers of hypoxia and angiogenesis in patients with PCC/PGL. Tissue microarrays sections including consecutive cases diagnosed between 1983–2011 were stained for PD-L1 and 2, hypoxia inducible factor 1a (Hif-1a), Carbonic Anhydrase IX (CaIX), Vascular Endothelial Growth Factor-A (VEGF-A). We explored the biologic significance of PD ligands expression using gene set enrichment analysis (GSEA) on The Cancer Genome Atlas (TCGA) for PCC/PGL (n = 184). In total, 100 patients, 10% malignant, 64% PCC, 29% familial with median tumor size of 4.7 cm (range 1–14) were included. Median follow-up was 4.7 y. We found PD-L1 expression in 18% of PCC/PGL, which was independent of adverse pathological features including capsular (CI), vascular invasion (VI), necrosis (N) and expression of biomarkers of hypoxia. PD-L2 expression (16%) strongly correlated with CI, VI, N and malignant behavior (p < 0.05) and was associated with stronger Hif-1a and CaIX immunolabeling (p < 0.01). PD-L2 was predictive of shorter survival (162 versus 309 months, HR 3.1 95%CI 1.1–9.2, p = 0.02). GSEA on TGCA samples confirmed enrichment of transcripts involved in hypoxia and anti-cancer immunity. We report for the first time PD ligands expression in PCC/PGL with a distinctive prognostic, clinico-pathologic and immuno-biologic role. These findings support a potential therapeutic role for PD-1/PD-L1 targeted checkpoint inhibitors in these tumors. KEY MESSAGE The molecular mechanisms underlying immune evasion in malignant phaeochromocytomas and paragangliomas (PCC/PGL) are poorly understood. This study demonstrates for the first time a distinctive immune-biologic and prognostic role of programmed death ligands 1 and 2 (PD-L1, PD-L2), two actionable drivers of the anti-cancer immune response. RNA-sequencing of tumor tissues reveals enrichment of transcripts relating to hypoxia and immune-exhaustion to explain the adverse clinical course observed in PD-L2 overexpressing tumors. These findings provide a rationale for the development of anti PD-1 therapies in malignant PCC/PGL