(A) mCherry-expressing CADM1 KO and control A549 cells were subcutaneously implanted into the dorsal flanks of RAG1–/– mice. Primary tumor growth was monitored, and mean tumor volumes are plotted; mean ± SEM shown. Data are representative of 1 experiment (n = 4–5 mice per group). (B) Overt lung nodules were counted on the excised lungs to assess spontaneous metastasis. Data represent 2 independent experiments, and pooled data are shown; error bars are SEM, and Mann-Whitney U test was performed, ****P < 0.0001. (C) Presence, or lack thereof, of metastatic spread was further confirmed by visualization of mCherry-positive tumor cells in the cross sections of the lungs by immunofluorescence. Top row scale bars: 500 μm; lower row: 50 μm, 100 μm, and 50μm, respectively.