CDKN2B and chordoma: Somatic duplications of the notochordal transcription factor brachyury (47, 48), chromosomal copy loss of phosphatase and tensin homolog (PTEN) (49), tuberous sclerosis complex (TSC) (50), cyclin-dependent kinase inhibitor 2A and 2B (CDKN2A and CDKN2B) (51), SMARCB1 (49), and PIK3CA (9) mutations are key aspects of chordoma pathogenesis, and therefore potential targets.