In order to address the above problem immunohistochemistry can be a useful tool in the diagnosis of some cases of melanoma, and markers such as S-100, HMB-45, Melan A, MITF, Ki-67, and p16 have been found to be useful in distinguishing between benign and malignant melanocytic lesions [7, 8]. The gene discussed is PMEL; the disease is melanoma.