Furthermore, CC10+ and SP-C+ double positive putative stem cells were rarely observed in urethane-induced tumors, either in CebpαΔ/Δ mice or long-observed control mice group (data not shown), suggesting that the tumor progression in CebpαΔ/Δ mice might not be associated with lung stem cell expansion. This evidence concerns the gene SCGB1A1 and neoplasm.