Single‐cell RNA sequencing reveals distinct immune cell subsets in phalangeal and soft‐tissue recurrence of giant cell tumor of bone

Abstract

Background: Giant cell tumor of the bone (GCTB), an intermediate locally aggressive neoplasm that frequently involves the epiphyseal region of the long bones. GCTB of the distal phalanx and soft-tissue recurrences are extremely rare. Little is known about the cellular and molecular differences between GCTB of the long bones and rare sites. Methods:We employed single-cell RNA sequencing to elucidate the transcriptional profiles of 28,992 cells originating from patients afflicted with GCTB in the femur, distal phalanx, and soft-tissue relapse. To confirm the critical findings, we subjected the paraffin sections of GCTB to immunohistochemical staining.Results: Our study revealed that GCTBs in rare sites display distinct immune subtypes and antigen presentation gene signatures. We observed minimal lymphocyte infiltration in GCTBs of the phalanx. Further analyses demonstrated that the transforming growth factor-β pathway and profibrotic proteins were significantly upregulated in phalanx lesions. In contrast, GCTB cells from soft-tissue recurrence exhibited discernible chondrocyte characteristics but presented lower antigen-presenting ability compared to those from femur lesions. Notably, we identified an immunosuppressive subset of mast cells in the soft-tissue recurrence. The secretion of proangiogenic and immunosuppressive factors from these mast cells suggests their potential role in the formation of vascular-rich and immunosuppressive niches in recurrent lesions.

Single-cell analysis reveals cellular reprogramming in advanced colon cancer following FOLFOX-bevacizumab treatment

“…The preparation of single-cell suspensions and scRNA-seq was conducted according to previously published methods (12,13). In brief, fresh tumor biopsy tissue was dissociated, erythrocytes were lysed, and cell viability was tested.…”

“…We identified cancer cells using epithelial cell marker genes (EPCAM, KRT19, KRT18) and inferred copy number variations (CNVs) profiles as previously described in our studies (12,13). We performed InferCNV within each sample using immune cells, including T cells, B cells, and myeloid cells, as the reference group and cancer cells as the observation group.…”