MYC Overexpression Drives Immune Evasion in Hepatocellular Carcinoma that is Reversible Through Restoration of Pro-Inflammatory Macrophages.

Cancers evade immune surveillance, which can be reversed through immune checkpoint therapy in a small subset of cases. Here we report that the MYC oncogene suppresses innate immune surveillance and drives resistance to immunotherapy. In 33 different human cancers, MYC genomic amplification and overexpression increased immune checkpoint expression, predicted non-responsiveness to immune checkpoint blockade, and was associated with both Th2-like immune profile and reduced CD8 T cell infiltration. MYC transcriptionally suppressed innate immunity and MHCI mediated antigen presentation, which in turn impeded T cell response. Combined, but not individual, blockade of PDL1 and CTLA4 could reverse MYC-driven immune suppression by leading to recruitment of pro-inflammatory antigen-presenting macrophages with increased CD40 and MHCII expression. Depletion of macrophages abrogated the anti-neoplastic effects of PDL1 and CTLA4 blockade in MYC-driven hepatocellular carcinoma (HCC). Hence, MYC is a predictor of immune checkpoint responsiveness and a key driver of immune evasion through the suppression of pro-inflammatory macrophages. The immune evasion by MYC in HCC can be overcome by combined PDL1 and CTLA4 blockade.