Parkinson disease and malignant melanoma in first-degree relatives of patients with early-onset melanoma

Cutaneous malignancies in patients with Parkinson's disease at a dermato-oncological university centre in Hungary

Background

The possible correlation between melanoma and Parkinson's disease (PD) has been intensively studied. In this work, we aimed to assess the coincidence of skin malignancies and PD at a dermato-oncological university centre in Central-Eastern Europe, Hungary.

Methods

From 2004 to 2017, a retrospective analysis of the centre's database was performed based on International Statistical Classification of Diseases-10 codes.

Results

Out of the patients who visited the clinic during the study period, 20,658 were treated for malignant skin tumours. Over the 14 years, 205 dermatological patients had PD simultaneously, 111 (54%) of whom had at least one type of skin malignancy: melanoma (n=22), basal cell carcinoma (BCC) (n=82), or squamous cell carcinoma (SCC) (n=36) (in some patients, multiple skin tumours were identified). Compared to the age- and sex-matched control group, patients with PD had a significantly lower risk for basal cell carcinoma (OR, 0.65; 95% CI, 0.47-0.89, p=0.0076) and for all skin tumours (OR, 0.74; 95% CI, 0.56-0.98, p=0.0392) but not for melanoma.

Conclusions

We found a decreased risk of all skin tumours and basal cell carcinoma and an unchanged risk of melanoma among patients with PD. However, it should be kept in mind that some large-scale meta-analyses suggest a higher incidence of melanoma after a diagnosis of PD, indicating the importance of skin examination in this vulnerable population.

Treatment with diphenyl-pyrazole compound anle138b/c reveals that α-synuclein protects melanoma cells from autophagic cell death

Recent epidemiological and clinical studies have reported a significantly increased risk for melanoma in people with Parkinson's disease. Because no evidence could be obtained that genetic factors are the reason for the association between these two diseases, we hypothesized that of the three major Parkinson's disease-related proteins-α-synuclein, LRRK2, and Parkin-α-synuclein might be a major link. Our data, presented here, demonstrate that α-synuclein promotes the survival of primary and metastatic melanoma cells, which is the exact opposite of the effect that α-synuclein has on dopaminergic neurons, where its accumulation causes neuronal dysfunction and death. Because this detrimental effect of α-synuclein on neurons can be rescued by the small molecule anle138b, we explored its effect on melanoma cells. We found that treatment with anle138b leads to massive melanoma cell death due to a major dysregulation of autophagy, suggesting that α-synuclein is highly beneficial to advanced melanoma because it ensures that autophagy is maintained at a homeostatic level that promotes and ensures the cell's survival.

The Presence of Alpha-Synuclein in Skin from Melanoma and Patients with Parkinson's Disease

Background

The misfolding and prion-like propagation of the protein α-synuclein (α-syn) is the leading molecular signature in Parkinson's disease (PD). There is a significant coincidence of PD and melanoma that may suggest a shared pathophysiology. This study compared the presence of α-syn in neural crest-derived tissues, such as nevi, melanoma, skin tags, and skin biopsies from patients with PD and healthy controls.

Methods

Biopsies from participants with PD were obtained from patients from a tertiary referral center for dermatology and neurology in Mexico and a private dermatopathology center in Florida between January 2015 and March 2016. Biopsies from 7 patients with melanoma, 15 with nevi, 9 with skin tags, 8 with PD, and 9 skin biopsies from healthy volunteers were analyzed for immunohistochemical determination of α-syn and tyrosinase. All analyses were performed by pathologists who were blinded with respect to the clinical diagnosis.

Results

In healthy controls, positive α-syn status was restricted to scattered cells in the basal layer of the epidermis and accounted for 1 ± 0.8% of the analyzed area. In patients with PD, there was increased staining for α-syn PD (3.3 ± 2.3%), with a higher percentage of positive cells in nevi (7.7 ± 5.5%) and melanoma (13.6 ± 3.5%). There was no increased staining in skin tags compared with healthy controls.

Conclusion

Patients with PD and melanoma have increased staining for α-syn in their skin. The authors propose that neurons and melanocytes, both derived from neuroectodermal cells, may share protein synthesis and regulation pathways that become dysfunctional in PD and melanoma.

Cutaneous malignant melanoma and Parkinson disease: Common pathways?

The mechanisms underlying the high prevalence of cutaneous malignant melanoma (CMM) in Parkinson disease (PD) are unclear, but plausibly involve common pathways. 129Ser-phosphorylated α-synuclein, a pathological PD hallmark, is abundantly expressed in CMM, but not in normal skin. In inherited PD, PARK genes harbor germline mutations; the same genes are somatically mutated in CMM, or their encoded proteins are involved in melanomagenesis. Conversely, genes associated with CMM affect PD risk. PD/CMM-targeted cells share neural crest origin and melanogenesis capability. Pigmentation gene variants may underlie their susceptibility. We review putative genetic intersections that may be suggestive of shared pathways in neurodegeneration/melanomagenesis. Ann Neurol 2016;80:811-820.

Parkinson disease (PARK) genes are somatically mutated in cutaneous melanoma

OBJECTIVE

To assess whether Parkinson disease (PD) genes are somatically mutated in cutaneous melanoma (CM) tissue, because CM occurs in patients with PD at higher rates than in the general population and PD is more common than expected in CM cohorts.

METHODS

We cross-referenced somatic mutations in metastatic CM detected by whole-exome sequencing with the 15 known PD (PARK) genes. We computed the empirical distribution of the sum of mutations in each gene (Smut) and of the number of tissue samples in which a given gene was mutated at least once (SSampl) for each of the analyzable genes, determined the 90th and 95th percentiles of the empirical distributions of these sums, and verified the location of PARK genes in these distributions. Identical analyses were applied to adenocarcinoma of lung (ADENOCA-LUNG) and squamous cell carcinoma of lung (SQUAMCA-LUNG). We also analyzed the distribution of the number of mutated PARK genes in CM samples vs the 2 lung cancers.

RESULTS

Somatic CM mutation analysis (n = 246) detected 315,914 mutations in 18,758 genes. Somatic CM mutations were found in 14 of 15 PARK genes. Forty-eight percent of CM samples carried ≥1 PARK mutation and 25% carried multiple PARK mutations. PARK8 mutations occurred above the 95th percentile of the empirical distribution for SMut and SSampl. Significantly more CM samples harbored multiple PARK gene mutations compared with SQUAMCA-LUNG (p = 0.0026) and with ADENOCA-LUNG (p < 0.0001).

CONCLUSIONS

The overrepresentation of somatic PARK mutations in CM suggests shared dysregulated pathways for CM and PD.

The role of the melanoma gene MC1R in Parkinson disease and REM sleep behavior disorder

The MC1R gene, suggested to be involved in Parkinson disease (PD) and melanoma, was sequenced in PD patients (n = 539) and controls (n = 265) from New York, and PD patients (n = 551), rapid eye movement sleep behavior disorder (RBD) patients (n = 351), and controls (n = 956) of European ancestry. Sixty-eight MC1R variants were identified, including 7 common variants with frequency > 0.01. None of the common variants was associated with PD or RBD in the different regression models. In a meta-analysis with fixed-effect model, the p.R160W variant was associated with an increased risk for PD (odds ratio = 1.22, 95% confidence interval = 1.02-1.47, p = 0.03) but with significant heterogeneity (p = 0.048). Removing one study that introduced the heterogeneity resulted in nonsignificant association (odds ratio = 1.11, 95% confidence interval, 0.92-1.35, p = 0.27, heterogeneity p = 0.57). Rare variants had similar frequencies in patients and controls (10.54% and 10.15%, respectively, p = 0.75), and no cumulative effect of carrying more than one MC1R variant was found. The present study does not support a role for the MC1R p.R160W and other variants in susceptibility for PD or RBD.

Parkinson's disease and cancer: A register-based family study

We wanted to compare cancer incidence rates between Parkinson's disease (PD) patients and persons without PD, as well as between siblings of these groups. We conducted a family-based matched cohort study based on nationwide Swedish health registries and the Swedish Multi-Generation Register. We assessed risk of incident cancer in PD patients (n = 11,786) during 1964-2009 versus a matched cohort of PD-free individuals (n = 58,930) and in siblings of PD patients (n = 16,841) versus siblings of PD-free individuals (n = 84,205). Hazard ratios with 95% confidence intervals were estimated using Cox proportional hazards regression. Cancer occurrence was slightly higher in PD patients than in PD-free individuals (hazard ratio (HR) = 1.05, 95% confidence interval (CI): 1.00, 1.10), largely because of cancers arising within 1 year before or after the index date for PD, but risk of smoking-related cancers was lower (HR = 0.87, 95% CI: 0.79, 0.96). PD patients had a higher risk of melanoma both up to 1 year before the PD index date (HR = 1.53, 95% CI: 1.23, 1.91) and from 1 year after the index date onward (HR = 1.46, 95% CI: 1.01, 2.10). In the sibling comparison, cancer occurrence was largely similar. These results indicate that melanoma risk is higher among PD patients and that mechanisms other than familial ones explain the association.

Susceptibility loci for pigmentation and melanoma in relation to Parkinson's disease

Growing evidence suggests that Parkinson's disease (PD) patients have a lower risk for most types of cancer except for melanoma, which has a modest positive association with PD. Pigmentation genes have been hypothesized to contribute to this association. We therefore examined whether genetic susceptibility loci for pigmentation or melanoma was associated with PD risk in 2 large independent datasets. In the Parkinson's Genes and Environment (PAGE) study, we examined 11 single-nucleotide polymorphisms (SNPs) identified from previous genome-wide association studies (GWAS) of pigmentation or melanoma in relation to PD among 808 PD cases and 1623 controls; furthermore, we also examined the colors of hair, eye, or skin and melanoma in relation to PD. In the International Parkinson's Disease Genomic Consortium (IPDGC), we examined a broader selection of 360 pigmentation or melanoma GWAS SNPs in relation to PD among 5,333 PD cases and 12,019 controls. All participants were non-Hispanic Whites. As expected, in the PAGE study, most SNPs were associated with 1 or more pigmentation phenotypes. However, neither these SNPs nor pigmentation phenotypes were associated with PD risk after Bonferroni correction with the exception of rs4911414 at the ASIP gene (p = .001). A total of 18 PD cases (2.2%) and 26 controls (1.6%) had a diagnosis of melanoma with an odds ratio of 1.3 (95% confidence interval: 0.7-2.4). In the IPDGC analysis, none of the 360 SNPs, including rs4911414, were associated with PD risk after adjusting for multiple comparisons. In conclusion, we did not find significant associations between GWAS SNPs of pigmentation or melanoma and the risk for PD.

Malignant melanoma, breast cancer and other cancers in patients with Parkinson's disease

Previous studies report an atypical cancer pattern among patients with Parkinson's disease. Here, we evaluate the cancer pattern among people diagnosed with Parkinson's disease in an extension of our previous cohort study. For this Danish population-based cohort study, we identified 20,000 people with Parkinson's disease diagnosed in 1977-2006, from the National Danish Hospital Register. Cohort members were followed up for cancer in the Danish Cancer Registry until December 31, 2008, and their incidence rates of cancer were compared to age-, sex- and calendar period-specific rates in the general population as standardized incidence rate ratios (SIRs). In subanalyses, we estimated the risk for cancer among patients with early onset Parkinson's disease and we also compared breast tumor characteristics among women with Parkinson's disease to that of a control group. The overall cancer risk in our cohort was decreased [SIR = 0.86; 95% confidence interval (CI) = 0.83-0.90], as were those for smoking-related (SIR = 0.65; 95% CI = 0.60-0.70) and nonsmoking-related cancers (SIR = 0.79; 95% CI = 0.71-0.86). The cohort had increased risks for malignant melanoma (SIR = 1.41; 95% CI = 1.09-1.80), nonmelanoma skin cancer (SIR = 1.29; 95% CI = 1.18-1.39) and female breast cancer (SIR = 1.17; 95% CI = 1.02-1.34). Among patients with early onset Parkinson's disease, the risk for cancer was comparable to that of the general population. Of breast tumor characteristics, only grade of malignancy differed between Parkinson's disease women and controls. This study confirms a lower cancer risk among people with Parkinson's disease. Increased risks for malignant melanoma, nonmelanoma skin cancer and breast cancer might be due to shared risk factors with Parkinson's disease.