HOPX and idiopathic pulmonary fibrosis: One of these is the aberrant basaloid cell (ABC), which is characterized by the expression of the basal cell marker KRT17 along with mesenchymal cell markers (FN1), senescence markers, IPF-associated molecules, while lacking canonical AEC markers such as SFTPC and homeodomain-only protein X (HOPX), which are specifically surrounded by fibrotic foci in patients with IPF [5, 6].