Study Suggests Genetic Link Between Parkinson's and Certain Cancers

Researchers at the University of Utah School of medicine have found evidence of a genetic link between Parkinson's disease (PD) and certain cancers. They reviewed death certificates for 700,000 people in the Utah Population Database, which spans more than 15 generations of Utah residents. The study revealed that people who died of Parkinson's disease and their first-, second- and third-degree relatives had a significantly higher rate of melanoma and an elevated rate of prostate cancer compared with the general population. Conversely, individuals whose death certificates noted a diagnosis of melanoma or prostate cancer were significantly more likely to die of Parkinson's disease, as were their first- and second-degree relatives; third-degree relatives were only marginally more likely to die of Parkinson's disease.

The researchers restricted their study to those people in the database for which there were at least 3 generations of genealogical data. Of these, 3000 died of Parkinson's disease. In a press release, co-author Stefan M. Pulst, MD, professor and chair of the department of neurology, said, "Collectively, these data strongly support a genetic association between Parkinson's disease and both prostate cancer and melanoma."

Lisa Cannon-Albright, professor of internal medicine and division chief of epidemiology at the university, suggested it might open the door to new areas of study. "Our findings point to the existence of underlying pathophysiologic changes that are common to Parkinson's disease, prostate cancer, and melanoma." 

The authors noted that the incidence of lung cancer was lower in patients who died of Parkinson's disease. Pulst said this was likely due to environmental and not genetic factors.

The data are being presented at the annual meeting of the American Academy of Neurology in Hawaii next week.

This is not the first study to link Parkinson's disease with cancer. Earlier studies have shown a decreased incidence of cancer overall in patients with Parkinson's, with the exception of melanoma. A few studies have suggested that patients with Parkinson's have a two-fold risk of developing melanoma.

In March 2010, the US Food and Drug Administration (FDA) reported that it was looking into links between entacapone and prostate cancer after data from a long-term clinical trial investigating an entacapone-based regimen in patients with Parkinson's disease demonstrated a higher rate of prostate cancer. The FDA said other studies had failed to find a similar link. Perhaps the findings from the study by Pulst and associates will help shed light on this concern.