S100B and melanoma: Moreover, SN-MM cell lines variably retained the expression of classical melanocytic markers, including the microphthalmia-associated transcription factor (MITF), human melanoma black 45 (HMB-45), melanoma antigen recognized by T cells 1 (MART-1), tyrosinase (TYR), and S100 calcium-binding protein B (S100), similarly to corresponding parental tumor biopsies (Additional file 7: Figure S1 and S2).