* mTOR signaling is hyperactive in sporadic sacral<unk> s: in one study 10 out of 10 sacral<unk> s exhibited phosphorylation of Ribosomal protein s6 and EIF4EBP1 by immunohistochemistry * Partial or complete PTEN (gene) deficiency is observed in nearly all sacral<unk> s * In a study of 49<unk> s Akt, TSC2, and EIF4EBP1 were phosphorylated in 92%, 96% and 98% of cases, respectively. * In a tissue microarray containing 21<unk> s Platelet-derived growth factor receptor-beta (PDGFR-b), epidermal growth factor receptor (EGFR), KIT (CD117) and HER2 were detected in 100%, 67%, 33% and 0% of cases, respectively. * The CDKN2A (p16) and CDKN2B (p15) loci on chromosome 9p21 are frequently deleted in<unk> s Another study found CDKN2A immunoreactivity in just 4% of cases. * 62% of<unk> s express the High Molecular Weight Melanoma Associated Antigen, also known as Chondroitin sulfate proteoglycan 4 (CSPG4) which has been the target of immune therapy. * In 2009, scientists discovered that an inherited gene duplication is responsible for the familial form of this disorder. Familial<unk>  are rare, with an estimated rate of 0.4% in all<unk> s.
Chordoma
Neurothekeoma
Brown tumor
Neuroma
Ependymoma
Germinoma
Ameloblastoma
Medulloblastoma