Exploring cancer in LRRK2 mutation carriers and idiopathic Parkinson's disease

Objectives: To compare the risk of non-skin cancer in LRRK2 mutation carriers and individuals with idiopathic Parkinson's disease (iPD), explore the age at which LRRK2 mutation carriers have cancer compared to iPD subjects, and clarify whether certain cancers are more closely associated with the LRRK2 mutation than iPD. Materials and Methods: Demographic data and cancer outcomes from 830 iPD patients and 103 LRRK2 mutation carriers (27 with PD) were retrospectively collected. Oncologic data were obtained from the Cancer Registry of Norway and included cancer type and age at cancer. All study participants were of Norwegian ethnicity. Results: LRRK2 mutation carriers have increased risk of non-skin cancer compared with iPD subjects (OR 2.09; 95% CI 1.16-3.77; p=.015). A significant association was found between the mutation and breast cancer in women (OR 4.58; 95% CI 1.45-14.51; p=.010). No other associations between harboring a LRRK2 mutation and specific cancer types were uncovered. Conclusion: LRRK2 mutation carriers have an increased risk of non-skin cancer compared with iPD subjects, which was mainly driven by the association between harboring the mutation and breast cancer in women. The increased risk is likely independent of ethnicity.