Notably, paired comparison of metastasis-free (no detectable GFP+ cells) and positive sections (at least one GFP+ cell) within the same lung from metastasis-bearing mice (Fig. 1C, Supplemental Fig. 1D) demonstrated a significant increase in CD45+ cells in relation to metastatic tumor cells on day 3 p.i. compared with day 1 p.i. (Fig. 1D). Here, PTPRC is linked to neoplasm.