ATM and idiopathic pulmonary fibrosis: As summarized in Fig. 5, a loss of transcripts encoding for components of various DNA damage response and repair proteins were observed in both rapid-IPF SSEA4+ (Fig. 5a) and SSEA4− cells (i.e. progeny) (Fig. 5b), including role of BRCA1 in DNA damage response, ATM signaling, mismatch repair in eukaryotes, BER pathway and Cell cycle: G2/M DNA damage checkpoint regulation pathways compared with the normal mesenchymal progenitors and progeny.