To focus on epithelial cells, studies comparing CFBE41o- cells (a bronchial epithelial cell line homozygous for the F508del mutation but not expressing any CFTR protein, representing the CF phenotype), and CFBE41o- cells transduced with lentiviral vector containing WT-CFTR (representing the non-CF phenotype) indicated a ceramide imbalance similar to that described above for CF mice38. This evidence concerns the gene CFTR and cystic fibrosis.