Clinical value of thioldisulphite homeostasis in patients with breast cancer

CLINICAL VALUE OF THIOLDISULPHITE HOMEOSTASIS IN PATIENTS WITH BREAST CANCER Purpose: Breast cancer is the second most frequently diagnosed malignancy in the world, after lung cancer, with more than two million cases each year(1). Many mechanisms are responsible for the pathogenesis of breast cancer. One of them is oxidative stress. Reactive oxygen species (ROS) formed as a result of oxidative stress play a role in cancer formation by affecting cell components such as lipid, protein and DNA(2). Thiols are important antioxidant agents in the organism and have an important defense role against ROS. In this prospective study, we aimed to show the clinical value of thioldisulfite homeostasis in breast cancer and its relationship with other clinical parameters. Methods: In this prospectively designed study, 40 female patients with new breast cancer and 33 healthy women without any additional disease who applied to the Dicle University Medical Faculty Oncology policlinic between 15.04.2021 and 30.09.2021 were included. Clinical information, demographic characteristics (age, height, weight, habits, comorbidity, performance status, family history, tumor stage) and routine examinations (hemogram, ALT, AST, bilirubin, lactate dehydrogenase) of the patients at diagnosis and before treatment, hospital registry system was obtained using. Serum native thiol, disulfide, total thiol, IMA levels and disulfide/native thiol, disulfide/total thiol and native thiol/total thiol ratios were analyzed using a new colorimetric method. In addition, tanita measurement was performed in order to measure the fatmass ratios of the patient group, and no tests were performed other than thioldisulfide in healthy individuals. Results: Serum native thiol level was lower in breast cancer patients (421.94 ± 96.87) compared to healthy controls (461.30 ± 74.87), but it was not statistically significant (p=0.060). Serum total thiol level was statistically significantly lower in breast cancer patients (462.45 ± 100.2) compared to healthy controls (507.28 ± 75.72) (p=0.038). Serum disulfide level was statistically significantly lower in breast cancer patients (20.25 ± 5.94) compared to healthy controls (22.99 ± 3.56) (p=0.018). The level of IMA was statistically significantly higher in breast cancer patients (0.81 ± 0.73) than in healthy controls (0.73 ± 0.39) (p=0.016). Native thiol and total thiol levels were moderately correlated with fatmass percentage and BMI, and weakly correlated with age in our breast cancer patients (p<0.05). In addition, univariant and multivariant analysis evaluating the relationship between thioldisulfite levels and clinical features of patients showed that native thiol and total thiol levels were statistically significantly correlated with BMI and menopausal status (p<0.05). It has been shown that native thiol and total thiol levels are low in postmenopausal patients and those with high BMI. No significant difference was found between breast cancer subtypes and clinical stages in terms of thioldisulfite levels (p>0.05). Conclusion: In our study, total thiol levels were found to be significantly lower in patients with breast cancer. In addition, it has been shown that thioldisulfite levels are associated with clinical features such as menopausal status and BMI. It can be thought that thioldisulfite homeostasis plays a role in the pathophysiology of breast cancer.