CCND1 and idiopathic pulmonary fibrosis: By using scRNAseq on human lung samples, it has been demonstrated that ATII cells present with higher senescence markers (such as CDKN1A/p21, CDKN2A/p16, TP53, MDM2, and CCND1) were higher in IPF lung samples when compared to controls, as well as demonstrating higher activation of senescence-related pathways such as oxidative phosphorylation, mitochondrial dysfunction, and the sirtuin signaling pathway [64].