Neurology 2016 Sep 24;87(12):1250-7. Epub 2016 Aug 24.
From the Neuromuscular Unit, Neurology Department (R.F.-T., M.M., J.-J.P., J.-B.E., A.L.d.M.), and Department of Pathology (I.R.), Donostia Universitary Hospital, San Sebastian; Neurosciences Area (R.F.-T., M.Z., D.O., A.L.d.M.) and Oncology Area (M.G.-P., A.M.), Biodonostia Institute, San Sebastian; Center for Biomedical Research Network in Neurodegenerative Diseases (CIBERNED) (R.F.-T., A.L.d.M.), Institute Carlos III, Ministry of Economy and Competitiveness; Clinical Epidemiology Unit (J.-I.E.), Donostia Universitary Hospital, CIBER-ESP, San Sebastian, Spain; Neuromuscular Area (A.-M.C.), AP-HP Hôpital Marin de Hendaye, France; Molecular Genetics Section (L.M.), Hospital Sant Joan de Deu, Barcelona; and Department of Neurosciences (A.L.d.M.), University of the Basque Country, UPV/EHU, San Sebastian, Spain.
Objective: Describe the incidence of cancer in a large cohort of patients with myotonic dystrophy type 1 (DM1) and to unravel the underlying molecular mechanisms.
Methods: Standardized incidence ratios (SIRs) were calculated in the Gipuzkoa DM1 cohort (1985-2013), dividing observed numbers by expected numbers for all cancers combined and stratified by sex. An estimation of the expected incidence was achieved by multiplying the age- and sex-specific incidence rates from the Basque population cancer registry by the person-years observed in the study cohort. Large-scale gene expression of peripheral blood mononuclear cell samples derived from 10 individuals with DM1 (5 men, 5 women) and 10 healthy matched controls was analyzed by the Human Gene 1.0 ST Affymetrix microarray.
Results: During 18,796 person-years of follow-up, corresponding to 424 patients with DM1, we observed 70 cancers in 62 patients giving a 1.81-fold risk (95% confidence interval [CI] 1.37-2.36), which was stronger in women than in men. Ovary (SIR 8.33, 95% CI 1.72-24.31) and endometrium (SIR 6.86, 95% CI 2.23-16.02) in women and thyroid (SIR 23.33, 95% CI 9.38-48.08) and brain (SIR 9.80, 95% CI 3.18-22.88) in both sexes were tumor sites with significantly higher risks in DM1. There were differences in gene expression between healthy controls and patients with DM1 and between men and women with DM1; all patients with DM1 combined and female patients with DM1 displayed significant downregulation of the microRNA (miRNA)-200c/141 tumor suppressor family.
Conclusions: Oncologic risk is increased in DM1, especially in women and for gynecologic, brain, and thyroid cancer. Expression of the miRNA-200/miRNA-141 tumor suppressor family is decreased in women with DM1.