Effect of navtemadlin on systemic dissemination of EBV-positive PTLD lymphoma. Photomicrographs show representative immunohistochemical staining of human CD20 in the liver, spleen, lung, and kidney of 2 control-treated and navtemadlin-treated mice bearing TRL1 and TRL595 tumors. Tumor nodules and clusters of tumor cells were detected in all organs tested in all control mice. No tumor cells were detected in all organs tested in all navtemadlin-treated mice, except that microscopic nodules were observed in liver of TRL595 mice (arrow).