They also demonstrated increased levels of leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) in basal cells, AT2 cells and intermediate alveolar progenitor populations located in fibrotic regions and in areas of inflammatory infiltration in COPD and IPF lungs that were associated with increased levels of p21 senescence marker. Here, LGR6 is linked to chronic obstructive pulmonary disease.