,33 Therefore, we studied whether inducing MMR deficiency in neuroblastoma tumors recapitulates some of the negative tumor-intrinsic features of MSI-high cancers, such as lower MHC class I levels, which can potentially play a role in the lack of therapeutic efficacy of anti-PD1 treatment against idMMR neuroblastoma tumors. The gene discussed is PDCD1; the disease is neuroblastoma.