9 , 10 Two case studies 1 , 2 reported that nulliparous women younger than 45 years of age with breast cancer did not show a left-sided predominance, and a large population-based study reported that left-sided predominance increased with age at diagnosis and was of borderline significance in women younger than 55 years of age. 8 , 9 In the present analysis, age and ethnicity were unrelated to breast cancer laterality.
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