KRT7 and neoplasm: Mice injected with BEAS-C LCSs (4 × 103, 4 × 104) yielded no tumor (n = 8 mice/group) whereas LCSs derived from BEAS-Akt1-E17K cells (4 × 103, 4 × 104) promoted formation of poorly differentiated carcinomas positive for cytokeratins (CK7, CK34) in 7/8 and 8/8 mice, respectively (Figure 1E, 1F).