Parkinson Disease Linked to Prostate Cancer, Melanoma
The association with prostate cancer extended to first-, second-, and third-degree relatives and, for melanoma, “extended the finding to include a significantly increased risk in relatives,” which is “strongly” supportive of a genetic link, noted Seth A. Kareus, MD, of the University of Utah, Salt Lake City, UT, and colleagues. “This conclusion is further strengthened by observation of the reciprocal relationship, an increased risk for PD in relatives of individuals with melanoma or prostate cancer.”
The study evaluated the relationship between PD and cancer subtypes using a computerized genealogy for approximately 2.3 million Utah pioneers and their descendants linked to the Utah Cancer Registry, comprising data on 100,817 individuals with a diagnosis of cancer. Between 1904 and 2008, PD was listed as a cause of death for 2,998 individuals; 212 had prostate cancer (RR, 1.71; 95% CI, 1.49–1.96) and 48 had melanoma (RR 1.95; (95% CI, 1.44–2.59)
Cases of colorectal, lung, pancreas, and stomach cancers were observed in deficit. Among 22,147 cases of prostate cancer and their relatives, a reciprocal significantly increased risk for PD was found, as it was among 7,841 cases of melanoma and their relatives.
“Identifying a genetic relationship between PD and cancer is critical to understanding underlying pathophysiologic changes in both diseases,” they wrote. “Understanding this relationship could allow clinicians to provide proper assessment of cancer risk in patients with PD and might also have implications for the counseling of relatives of patients.”
An accompanying editorial noted, “If the mechanisms are primarily genetic…then it may be possible to identify genetic variants that predispose to accelerated neurodegeneration and to increased oncogenesis in the same individual or among members of some particular families. On the other hand, if PD is multifactorial at the individual level, dimorphic in men and women, and heterogeneous at the population level, the search for one or several genetic variants may not be productive.”