Inspection of images from IFM2 high tumors exhibiting slow progression (for example, participant C34) revealed high numbers of PD-L1+ cells (Fig. 5d and Extended Data Fig. 6e) adjacent to pan-cytokeratin+ tumor cells; based on overlap of PD-L1, CD68 and CD45 staining, we conclude that PD-L1+ cells are likely myeloid in origin, as described previously15. Here, PTPRC is linked to neoplasm.