HMB 45 is a tumor marker for
Malignant melanoma expresses HMB45 ,S-100 and vimentin 
HMB 45 is present in melanosome and is more specific 
S-100 is more sensitive but is non specific (also present in LAngerhan's cell histiocytosis, neural tumors and sarcomas like Liposarcoma and Chondrosarcoma)
Neuroblastoma
Neurofibroma
Malignant melanoma
Angiosarcoma