Osteosarcoma (OS) is a heterogeneous and aggressive bone cancer. This study used single-cell RNA sequencing (scRNA-seq) to analyze the tumor microenvironment (TME) in six treatment-naïve dogs with spontaneously occurring primary OS. Analysis of 35,310 cells identified 41 distinct cell types, including follicular helper T cells, mature regulatory dendritic cells (mregDCs), and eight tumor-associated macrophage (TAM) populations. Cell-cell interaction analysis suggested key roles for mregDCs and TAMs in modulating T cell immunity. Cross-species analysis showed high similarity between human and canine OS, making canine OS a valuable translational research model for immuno-oncology.

Dylan T. Ammons, Leone S. Hopkins, Kathryn E. Cronise, Jade Kurihara, Daniel P. Regan, Steven Dow