Examples include TP63+KRT17+KRT5− basal-like or aberrant basaloid cells and SCGB3A2+ distal airway specific secretory cells which have been identified in IPF, COPD, and other advanced parenchymal lung diseases, with a suggestion of interrupted cell type transitions in an effort to repair6,8,9,22,65,66. This evidence concerns the gene KRT5 and chronic obstructive pulmonary disease.