PTPN11 and pilocytic astrocytoma: Gain-of-function mutations in the SHP2 gene, PTPN11, have been identified in Noonan Syndrome42, haematological malignancies43, 44, 45, 46, 47 and other types of cancers, including breast cancer48, lung cancer, neuroblastoma, pilocytic astrocytoma and medulloblastoma49, 50, 51, 52, 53, 54.