Introduction
Pleuropulmonary blastoma (PPB) is a rare (<2/1 000 000) primary pulmonary malignancy with a poor prognosis in children1, which is a pulmonary soft tissue sarcoma. It is generally believed that PPB originates from mesenchyme and might be related to pulmonary or pleural development2. PPB is related to DICER1 gene mutations (mostly biallelicDICER1 mutations, nonsense mutations, and code shift mutations)3 accompanied by overexpression of Neural cell adhesion molecule (NCAM) 1 and Fibroblast growth factor (FGF) 94 relevant to fetal lung development5. However, the cellular components of this tumor and the interactions between the various cell types are unknown.
Single-cell RNA sequencing (scRNA-seq) is a sequencing technology that obtains genetic information of a single cell. Compared with traditional technologies conducted at the multi-cell level, scRNA-seq has a higher resolution that determines precise gene expression patterns of thousands of single cells, putting more emphasis on the heterogeneity of genetic information. This technology is used in tumor research and facilitates the isolation and definition of cell subpopulations. Moreover, the differentiation of histologically similar cells, evolution of the tumor, and relationship between the tumor and its microenvironment can be well understood and explored using scRNA-seq6,7.
Although some progress has been made in the study of gene mutations and pathological changes of PPB, the heterogeneity of the tumor and its specific developmental process remain unclear. Here, we applied a PPB sample from the pediatric hospital affiliated to Fudan University to single cell sequencing to define the approximate landscape of this tumor and explore the differentiation trajectory of PPB.