Conservatively to human data (2, 3, 20), canine lung epithelial cells spread into alveolar type 2 cells (overexpressing genes of surfactant proteins and napsin A protein, the latter being used as a lung carcinoma marker in dogs), alveolar type 1 cells (expressing AGER), secretory cells (expressing SCGB1A1, MUC5B), basal cells (expressing KRT14 and transcription factor TP63) and ciliated cells (expressing CAPS, FOXJ1, CCDC78, HYDIN). Here, SCGB1A1 is linked to lung carcinoma.