CD34 and neoplasm: We found that, while GFP+ Mc38 cells just began to colonize (Supplementary Fig. S1B, S1C); some CD34+ staining showed even before tumor cells arrived (Supplementary Fig. S1B and S1C, the 2nd columns: CD34+ vs. GFP+ staining); later an intensive CD34+ staining almost overlapped with that of GFP+ on bigger metastases.