Abstract
PURPOSE: Manganese superoxide dismutase (MnSOD) is one of the major enzymes implicated in the cellular defence against reactive oxygen species. Low expression of MnSOD has been observed in different cancer tissues and several reports have shown that overexpression of MnSOD inhibits growth in various human cancer cells. These observations suggest that MnSOD is involved in carcinogenesis. A polymorphism (Ala-9Val) in the mitochondrial targeting sequence (MTS) of the MnSOD gene has been proposed to affect protein localization and thereby influence cellular defence against superoxide radicals. METHODS: In the present case-control study, including 118 early onset breast cancer patients (