This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'S100 is a marker used in the diagnosis of all Except \nSelect and explain. \nA. Melanoma, B. Schwannoma, C. Histiocytoma, D. Basal cell cancer', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Acidic protein, 100% Soluble in ammonium sulfate at neutral pH (derivation of name) S100 protein family is multigenic group of nonubiquitous cytoplasmic EF-hand Ca2+-binding proteins, sharing significant structural similarities at both genomic and protein levels; S100 protein family has 24 known human members each coded by a separate gene; at least 19 on chromosome 1q21 Helps regulate cell contraction, motility, growth, differentiation, cell cycle progression, transcription and secretion Structurally similar to calmodulin', 'role': 'assistant'}]