CTLA4 and cancer: More recently, we reported that expression of DUX4 in primary cancers and engineered cancer cell lines blocks the interferon-gamma (IFNγ)-mediated induction of major histocompatibility complex class I (MHC class I) antigen presentation and promotes resistance to immune checkpoint blockade treatments, such as anti-CTLA-4 and anti-PD-1 therapies (Chew et al., 2019).