CD200 and neoplasm: From baseline CD200 tumor cell membrane staining intensity and CD200R1 immune cell staining using validated assays, a potential trend between CD200 expression level (H-score) on tumor cells with clinical benefit (PR/SD versus PD) in participants treated with pharmacologic doses (≥60 mg) 23ME-00610 was observed (Fig. 3C; Supplementary Fig. S3C).