Melanoma is a type of skin cancer that develops from melanocytes, and Parkinson’s disease (PD) is a progressive movement disorder that affects the nervous system… But did you know that these two conditions have something in common?
Research shows that PD patients have a higher risk of developing melanoma, and melanoma patients have a higher risk of developing PD. But what causes this relationship? How does family history increase your risk? And what should you do next?
The relationship between melanoma & Parkinson’s
The relationship between melanoma and PD runs both ways: Specifically, PD patients are 4x more likely to develop melanoma, and melanoma patients have 4x the risk of developing PD.1 Even given these statistics, it is important to know that many PD patients will not develop melanoma, and many melanoma patients will not develop PD. However, if you are affected by either of these conditions, you should talk to your doctor about your risk factors.
What about family history?
Melanoma and PD are both independently associated with family history: A person’s risk of melanoma increases if someone in their family has also experienced melanoma, and a person’s risk of PD increases (slightly) if they have a family history of PD. More surprisingly, a family history of one of these conditions may also impact your likelihood of being diagnosed with the other: Research shows that people with a family history of melanoma (in a first degree relative) have twice the risk of developing PD.2 When possible, always keep your family medical history up-to-date, but if you have melanoma or PD, and have a family history of either of these conditions, be sure to talk to your healthcare providers.
Why is there an association between Parkinson’s & melanoma?
Since the 1970s, researchers believed that levodopa (a common therapy for Parkinson’s disease) caused melanoma in Parkinson’s patients.1,3,4 Levodopa impacts the body’s creation of melanin and melanocytes, leading scientists to blame this drug for higher incidence of melanoma in PD patients. Many research studies have since reported that levodopa does not cause melanoma, but no one knows exactly why this association between melanoma and PD exists.2,4
Although the exact relationship between PD and melanoma is still a mystery, researchers have suggested many other reasons for this association, including social-environmental factors, immune system irregularities, and genetics.
Both PD and melanoma are associated with melanin (the pigment that colors your hair, skin, and eyes)5. PD is caused by the death of dopamine-producing cells (which are high in melanin), while melanoma results from the overproduction of melanin-creating cells. Although these changes are different (PD results from the loss of cells, while melanoma results from the overproduction of cells), both conditions result from melanin-related abnormalities. Therefore, some researchers believe that PD and melanoma patients share the same immune system irregularities2.
Melanoma and PD are associated with some of the same non-changeable, genetic factors, such as race, sex, and skin type. Your risk of PD and your risk of melanoma both increase if you are a man, if you are White, and/or if you have fair skin.6,7 Therefore, based on these genetic similarities, some researchers believe that the same genetic abnormality affects both PD and melanoma patients.1,3
What should I do if I have Parkinson’s disease?
PD patients should have regular screenings for melanoma, which may include seeing a dermatologist for a total body skin exam.1,2,4 Individuals affected by PD should also take steps to minimize their risk of melanoma, such as reducing UV exposure and checking your skin regularly for any changes. You should also talk to your PD providers about melanoma.
What should I do if I have a history of melanoma?
Unlike melanoma, PD is an idiopathic disease, meaning that it occurs spontaneously, without a known cause. Therefore, melanoma patients cannot take steps to prevent PD. However, if have a history of melanoma, you can work with your healthcare provider to look for early symptoms of Parkinson’s disease, as well as discuss your family history.
Newman, Tim. "Link between Parkinson's and Melanoma Runs Both Ways." Medical News Today, 5 July 2017, www.medicalnewstoday.com/articles/318245.php. Accessed 13 July 2017
Huang, Pei, et al. "The Association Between Parkinson's Disease and Melanoma: A Systematic Review and Meta-Analysis." Translational Neurodegernation, vol. 4, no. 21, 3 Nov. 2015, www.ncbi.nlm.nih.gov/pmc/articles/PMC4631109/. Accessed 13 July 2017.
Gao, X. "Family History of Melanoma and Parkinson Disease Risk." Neurology, vol. 73, 2009, pp. 1286-91, www.ncbi.nlm.nih.gov/pmc/articles/PMC2764417/. Accessed 13 July 2017.
Dalvin, Lauren A., et al. "Parkinson Disease and Melanoma: Confirming and Reexamining an Association." Mayo Clinic, Mayo Clinic Proceedings ser., vol. 92, no. 7, July 2017, pp. 1070-79, doi:10.1016/j.mayocp.2017.03.014. Accessed 13 July 2017.
Dolhun, Rachel. "Ask the MD: Parkinson's Disease and Melanoma." The Michael J. Fox Foundation for Parkinson's Research, 26 May 2015, www.michaeljfox.org/foundation/news-detail.php?ask-the-md-parkinson-disease-and-melanoma. Accessed 13 July 2017.
"How Common Is Parkinson’s Disease?" net, Health Union, parkinsonsdisease.net/basics/statistics/. Accessed 14 July 2017.
"What is Skin Cancer?" net, Health Union, skincancer.net/basics/. Accessed 14 July 2017.