A review of the association between Parkinson disease and malignant melanoma

BACKGROUND An association between melanoma and Parkinson disease (PD) has been hinted at in the neurology and oncology literature since the 1970s after the initiation of levodopa (L-DOPA) therapy for PD. Given that L-DOPA is a substrate in melanin synthesis, there existed a concern that this therapy might cause melanoma. OBJECTIVE The objective was to research possible etiological links to explain the connection between PD and melanoma. METHODS A PubMed and Google Scholar literature search was performed using access provided by the University of Minnesota biomedical library. RESULTS Patients with PD have an overall decreased risk of cancer diagnoses. However, breast cancer and melanoma have an uncharacteristically high rate of co-occurrence with PD. Family history of melanoma and lighter hair and skin color confer a higher risk of developing PD, and having a first-degree relative with either disease conveys a significantly increased risk of developing the other. Other possible connections that have been explored include pigmentation genes in neural-derived cells, pesticides, MC1R polymorphisms, and abnormal cellular autophagy. CONCLUSION Although a link between PD andmelanoma exists, the etiology of this link continues to be elusive. Both PD and melanoma are likely multifactorial diseases involving genetic and environmental risk factors.