title: Studies of cancer etiology in the Danish twin population. I. Breast cancer.
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D003718:Denmark; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D011247:Pregnancy; D012042:Registries; D012189:Retrospective Studies; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic