High serum iron and zinc decrease glutathione S-transferase among women with breast cancer

Abstract

UNIVERSA MEDICINAHigh serum iron and zinc decrease glutathione S-transferase among women with breast cancer Nendyah Roestijawati*, Dwi Arini Ernawati*, and Diah Krisnansari* BACKGROUND Breast cancer in Indonesia ranks second as the most common cancer found in women after cervical cancer. Tumor cells express increased levels of antioxidant proteins to detoxify reactive oxygen species (ROS). Glutathione S-transferase (GST) is known to play a key role in the detoxification and reduction of ROS. Trace elements have nutritional benefits as essential cofactors for physiologic processes, but some can be toxic to humans. Accumulated evidence suggests that deficiency or excess of certain trace elements may be associated with risk of chronic diseases including cardiovascular diseases, diabetes and cancer. The aim of this research was to determine the correlation of the trace elements iron and zinc with the oxidative stress level of GST activity in women with breast cancer. METHODSAn observational analytic study with cross sectional design was conducted involving 35 breast cancer women. Research subjects were women with breast cancer diagnosed by biopsy. Measurements of iron and zinc levels were performed using atomic absorption spectrometry, GST activity was measured using spectrophotometry. Data analysis was done with the Pearson correlation test. RESULTSThe results showed that there was a significant relationship of serum iron with GST (r=-0.487; p<0.05) and serum zinc with GST (r=-0.409; p<0.01). CONCLUSIONOur study demonstrated that the higher zinc and iron level, the lower GST level among breast cancer women. It is recommended to use zinc, iron and GST levels as biomarkers for breast cancer and its progression.

Iron intake, oxidative stress‐related genes and breast cancer risk

“…Several studies assessing other prooxidant exposures (e.g., smoking, alcohol) also reported stronger positive associations in women with null GSTT1 and/or GSTM1 genotypes . In addition, the possible interplay between iron and GST in breast cancer is supported by a recent study reporting a negative correlation between serum iron and GST enzyme activity among breast cancer patients …”

“…20,45,46 In addition, the possible interplay between iron and GST in breast cancer is supported by a recent study reporting a negative correlation between serum iron and GST enzyme activity among breast cancer patients. 47 Unlike GSTs, MnSOD is a mitochondrial enzyme that plays a role in antioxidant defense by catalyzing the conversion of superoxide anions to hydrogen peroxide. 48 The Val16Ala SNP, which alters enzyme structure and localization into the mitochondria, has been suggested to affect breast cancer susceptibility, although this is not supported by the current epidemiological literature.…”