Genomics and the Immune Landscape of Osteosarcoma.

Conventional osteosarcoma (OS) is a high-grade intraosseous malignancy with production of osteoid matrix; however, a deeper dive into the underlying genetics reveals genomic complexity and instability that result in significant tumor heterogeneity. While early karyotyping studies demonstrated aneuploidy with chromosomal complexity and structural rearrangements, further investigations have identified few recurrent genetic alterations with the exception of the tumor suppressors TP53 and RB1. More recent studies utilizing next-generation sequencing (NGS; whole-exome sequencing, WES; and whole-genome sequencing, WGS) reveal a genomic landscape predominantly characterized by somatic copy number alterations rather than point/indel mutations. Despite its genomic complexity, OS has shown variable immune infiltrate and limited immunogenicity. In the current chapter, we review the hallmarks of OS genomics across recent NGS studies and the immune profile of OS including a large institutional cohort of OS patients with recurrent and metastatic disease. Understanding the genomic and immune landscape of OS may provide opportunities for translation in both molecularly targeted therapies and novel immuno-oncology approaches.