Then, to identify the tissue of origin, morphological evaluation is supplemented by several immunohistochemistry (IHC) markers including thyroid transcription factor (TTF-1), chromogranin and synaptophysin for lung cancer BM (LCBM); GATA3 binding protein (GATA3), mammaglobin, gross cystic disease fluid protein 15 (GCDFP-15) and ER for BCBM; and human melanoma black 45 (HMB45), melanoma antigen recognized by T-cells 1 (Melan A/MART-1), SRY-Box 10 (SOX-10), and the S100 calcium binding proteins (S-100) for melanoma BM (MBM)9,10. The gene discussed is MLANA; the disease is melanoma.