S100A1 and melanoma: Tumor cells were further subdivided based on the expression of melanocytic lineage markers (e.g., MART1, S100A1), melanoma biomarkers commonly used in clinical practice for diagnosis (e.g., PRAME), differentiation markers (e.g., SOX9, SOX10, NGFR), and proliferation markers (e.g., KI67, pH3; see Supplementary Table S3 for index of gene and protein names).