We conjecture that this may be related to spontaneous tumor regression, which is prevalent in patients with NB younger than 12 months of age (30), and that spontaneous tumor regression may be associated with (I) neurotrophin deprivation, (II) loss of telomerase activity, (III) humoral or cellular immunity and (IV) alterations in epigenetic regulation and possibly other mechanisms (31). Here, BDNF is linked to neuroblastoma.