This report introduces some aspects of our current basic research focus on the unique metabolic pathways within the melanocyte. Using this approach, we hope to gain a better understanding of the pathophysiology of
malignant melanoma and develop early laboratory diagnostic tests for this disease. Specifically, we will discuss that: 1) the synthesis of
pheomelanin is markedly increased in
malignant melanoma and dysplastic
melanocytic nevi; 2) high levels of metabolites of
pheomelanin and
eumelanin can be detected in the urine and blood of patients with metastatic
melanoma; 3) this release of
melanin metabolites appears to correlate with
tumor thickness and
tumor load, including the extent of
metastasis; 4) the synthesis of melanosomal
proteins also becomes aberrant in
malignant melanoma; and 5) this abnormal melanosome synthesis can be utilized in the identification of antigenic
epitopes that are uniquely expressed in
malignant melanoma. We believe that this synthesis and secretion of abnormal
melanin pigment and melanosomal
proteins (human melanosome-specific
antigen) would be useful for the development of early laboratory diagnostic and monitoring tools for
malignant melanoma. In addition, we also report the detection of
pheomelanin component in "normal" unexposed skin; however, the relative amount of
pheomelanin in the skin does not reflect hair color (e.g., red hair). The nature of this
pheomelanin component in the skin needs to be further clarified.