S100B and neoplasm: Plausible explanations for this finding include the slow lesion dynamics of this type of tumour; slow-growing tumours may cause less blood-brain barrier disruption, and the damage to the structural network supporting the neurons may be so gradual that even if S100β were released, current techniques would not be sensitive enough to distinguish the level between persons with no CNS lesion and those with a lesion causing a gradual mass effect.