To determine the fate of ADAM12+ MSCs in vivo during tumor progression, we generated a tetracycline-regulated lineage-tracing system of ADAM12+ cells by crossing ADAM12-tTA mice27 with LC-1 mice and Rosa26STOPfloxYFP reporter mice (ADAM12-tTA-CreYFP mice, Fig. 5c). This evidence concerns the gene ADAM12 and neoplasm.