NGF and neoplasm: Type 1 comprise low-risk tumours with triploid DNA content, numeric alterations, and high expression of the nerve growth factor TrkA [10,11], Type 2A involve intermediate-risk tumours with high occurrence of 11q-deletion (del11q) and 17q gain (gain17q) but no MNA, and Type 2B comprise high-risk MYCN amplified tumours with high occurrence of gain17q and 1p-deletion (del1p) [12,13].