LGR5 and neoplasm: To investigate the effects of Lgr5-derived ECM1 on AT2 cells, we used an antibody to neutralize ECM1 in the supernatant of Lgr5 (Fig. 2d), and then cocultured with AT2 (Fig. 2c), and found that the colony formation and tumor initiation capacities of AT2 cells were significantly decreased (Fig. 2e, f), suggesting that Lgr5 cell-secreted ECM1 was crucial to the CSC-like property of AT2 cells.