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.