γ-glutamyl transferase levels linked to breast cancer risk
MedWire News: Premenopausal women with high serum γ-glutamyl transferase (GGT) levels have an increased risk for breast cancer, UK researchers report.
GGT is an enzyme that uniquely enables glutathione catabolism by hydrolyzing the γ-glutamyl bond between glutamate and cysteine. It has been implicated in several major diseases including cardiovascular disease, hepatobiliary disease, diabetes, and cancer, explain Ian Fentiman and Diane Allen from Guy’s Hospital in London.
In the present study, Fentiman and Allen measured serum GGT in 1803 women participating in the Guernsey Breast Cancer Cohort Study. Among these women, 96 went on to develop breast cancer between 21 months and 20 years after the blood sample was taken.
The researchers found a highly significant relationship between elevated GGT levels and breast cancer risk after adjustment for age at study entry, height, weight, and age at menarche and first birth with nulliparity.
Women who had GGT levels in the highest quartile (>14.0 OIU/l) of the normal range had a 2.17-fold increased risk for breast cancer compared with women in the lowest quartile (≤8.0 OIU/l).
When the researchers analyzed the results on the basis of menopausal status at the time of entry into the study, they found no relationship between GGT and breast cancer risk in postmenopausal women. In contrast, premenopausal women with GGT levels in the highest quartile had a 3.81-fold increased risk for breast cancer compared with women in the lowest quartile.
Furthermore, premenopausal women with serum GGT levels above the normal range (>40 IU/l) had a 4.9-fold increased risk for breast cancer compared with those with levels within the normal range.
“If these findings can be replicated in a larger study, they may afford a new and inexpensive opportunity to delineate women who are at high risk for breast cancer with the hope of targeting surveillance, allowing an earlier diagnosis and thereby reducing the mortality accruing from this disease,” write Fentiman and Allen in the British Journal of Cancer.
They conclude: “Serum GGT may mark previous exposure to carcinogens and lead to the identification of DNA adducts involved in mammary carcinogenesis.”
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By Laura Dean