Polymorphism in the manganese superoxide dismutase (MnSOD) gene and risk of breast cancer in young women.
OBJECTIVE
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 (<or=36 years) and 174 age-matched controls, the MTS polymorphism and loss of heterozygosity (LOH) in the locus of MnSOD were analysed.


RESULTS
We found that individuals with MnSOD(Val/Val) and MnSOD(Val/Ala) genotypes showed an increased risk of breast cancer (OR, 2.7; 95% CI, 2.2-5.5, p=0.01, OR, 3.0; 95%CI, 1.4-6.5, p=0.002). Moreover, 45% of the informative cases expressed allelic loss at the chromosomal locus of the MnSOD gene. No correlation was found between LOH and the genotype.


CONCLUSIONS
The present study suggests that MnSOD may be implicated in breast carcinogenesis in young women.
Bergman
Malin
M
Department of Biomedicine and Surgery, Division of Cell biology, Faculty of Health Sciences, University Hospital, 581 85, Linköping, Sweden.
Ahnström
Marie
M
Palmebäck Wegman
Pia
P
Wingren
Sten
S
D000328:Adult; D000483:Alleles; D001943:Breast Neoplasms / Q000201:enzymology* / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D018384:Oxidative Stress / Q000235:genetics; D011110:Polymorphism, Genetic; D012307:Risk Factors; D013482:Superoxide Dismutase / Q000235:genetics*
D013482:Superoxide Dismutase