Abstract

Background: Breast cancer remains the leading cause of cancer and the major cause of cancer-related deaths among women in Iraq. Mostly breast cancer patients are from the southern provinces of Iraq including Maysan governorate. Cytochrome P450 1B1 (CYP1B1) is the major enzyme in extrahepatic tissues that catalyzes the hydroxylation of 17-estradiol to 4-hydroxyoestradiol (4-OHE2), which is a genotoxic catechol estrogen resulting in the formation of depurinating DNA adducts in breast epithelial cells. Reduced glutathione (GSH) is the most abundant intracellular non-enzymatic antioxidant and the major defense against oxidative stress and catechol estrogen-induced DNA damage. Nitric oxide (NO) is a multifunctional signaling molecule that at high levels produced by inducible nitric oxide synthase (iNOS) overexpression in breast cancer tissue it functions to support tumor angiogenesis, immune suppression, and invasiveness. This study aims to examine the clinical biochemistry patterns of CYP1B1 activity, GSH, and NO in breast cancer patients compared with healthy individuals, and to determine their effectiveness as individual biomarkers for breast cancer diagnosis and tumor stage classification. Methods: A prospective case-control study was held in Maysan Oncology Center Amarah Iraq. Case Group (n = 40) consisted of females with breast cancer confirmed histopathologically and of all AJCC stages (8th edition), sampled before administration of any treatment. Control Group (n = 40) was made up of healthy women individually matched for age, menopausal status and BMI. CYP1B1 activity was determined using the 4-hydroxyoestradiol formation assay which is based on ELISA and is validated. GSH was determined by the Ellman (DTNB) colorimetric method. Nitric oxide was quantitated as total nitrite/nitrate by the Griess reagent assay. Results: Breast cancer patients showed Much higher CYP1B1 activity (61.8 9.3 vs. 28.4 4.6 pmol/mg protein/min; P < 0.001; Cohen's d = 4.38), a very sharp reduction in GSH levels (384.6 78.3 vs. 812.4 94.6 mol/L; P < 0.001; Cohen's d = 4.94) and a great increase in NO levels (48.3 9.7 vs. 18.6 4.2 mol/L; P < 0.001; Cohen's d = 3.91). All of the three markers exhibited progressive stage-dependent deterioration switching AJCC Stages IIV. Multivariate logistic regression established CYP1B1, GSH and NO as independent factors linked to breast cancer diagnosis. ROC analysis gave AUCs of 0.951, 0.938 and 0.926, respectively. Significant correlations were discovered between CYP1B1 activity and serum oestradiol (r = 0.641; P < 0.001), GSH (r = -0.712; P < 0.001) and tumor stage (r = 0.724; P < 0.001). Conclusion: The CYP1B1GSHNO triad represents a trio of biochemistry-based breast cancer detection methods that have been independently confirmed and are also easy to measure chemically. Their model, which focuses on the metabolism of oestrogen as the basis of breast cancer, is quite different from the oxidative stress panels described earlier, and is a reflection of the unique biochemical pathobiology of breast carcinogenesis. The implementation of this panel in clinical biochemistry practice at Maysan Oncology Centre would be a good move.