Fig. 1

KRAS expression in the normal human airway epithelium in vivo and in vitro a Immunohistochemical staining analysis of KRAS in the airway epithelium. Normal nonsmoker human airway sections were analyzed for expression of KRAS. Isotype specific antibody was used as negative control. Scale bar 20 μm. b Expression of KRAS during differentiation of human airway basal cells (BC) on air-liquid interface (ALI) culture. KRAS mRNA expression was assessed by qPCR. Data points indicate the mean of n = 3 independent experiments, each performed in triplicate with independent donors of BC. Error bars indicate standard error of the mean. c Immunohistochemical staining analysis of KRAS during ALI culture. ALI day 0 and day 28 sections were analyzed for expression of KRAS. Isotype specific antibody was used as negative control. Scale bar 20 μm