PTPRJ and pulmonary fibrosis: For example, Ptprj is known to exert an anti‐fibrotic effect in pulmonary fibrosis through interactions with syndecan‐2.[33] Furthermore, Ptprj can also regulate the activity of the nonreceptor tyrosine kinase protein proto‐oncogene tyrosine protein kinase Src[34] and numerous studies have shown that activated Src is a pivotal molecule in multiple fibrosis pathways.[35] Therefore, it is not difficult to see that Ptprj may have a long‐ignored, but vital role in organ fibrosis.