Manganese Superoxide Dismutase Alanine-to-Valine Polymorphism at Codon 16 and Lung Cancer Risk

Abstract
Manganese superoxide dismutase (MnSOD) catalyzes the dismutation of a specific type of reactive oxygen species, superoxide radicals, into hydrogen peroxide and oxygen (1). Accumulation of reactive oxygen species can damage DNA, proteins, and lipids, leading to the initiation or promotion of cancer (2,3). MnSOD, the only known superoxide scavenger in mitochondria, may be particularly important for antioxidant defense because mitochondria are the major sites for cellular metabolism and hence production of reactive oxygen species (4).