SEPTIN9 and neoplasm: SEPT9 in particular is not well understood in the human setting, but it has been suggested to be a tumor suppressor as well as a proto-oncogene16 and mutations in the SEPT9 gene have been shown to cause hereditary neuralgic amyotrophy17 due to loss of proper hetero-octamer formation with other septins18, disruption of proper microtubule bundling19 and impaired vesicular transport11.