Correlation Between CA-125 and Oxidative Stress in Ovarian Cancer
There is a demonstrated correlation between elevated CA-125 levels and increased oxidative stress in ovarian cancer patients, with both markers showing parallel increases in disease severity and stage progression.
Evidence of Direct Correlation
The relationship between CA-125 elevation and oxidative stress has been directly investigated in ovarian cancer populations:
Ovarian cancer patients demonstrate significantly elevated markers of oxidative stress (increased plasma TBARS and conjugated dienes) alongside significantly decreased antioxidant defenses (reduced SOD, catalase, vitamin C, and vitamin E) compared to healthy controls 1.
A significant negative correlation exists between tumor stage and antioxidant levels (SOD and GPX), while a significant positive correlation exists between tumor stage and lipid peroxidation markers (MDA) 2.
The oxidative stress pattern mirrors CA-125 behavior, as CA-125 levels also correlate positively with tumor burden and disease stage 3.
Mechanistic Understanding
The parallel elevation of both markers reflects underlying disease biology:
Increased lipid peroxidation in ovarian cancer may result from excessive oxidative stress caused by incessant ovulation or epithelial inflammation, the same processes that drive CA-125 production from mesothelial and epithelial cells 1.
Low antioxidant levels (SOD, catalase, vitamins C and E) in ovarian cancer patients likely result from increased utilization to scavenge lipid peroxides and sequestration by tumor cells 1.
Approximately 85% of advanced ovarian cancer patients have elevated CA-125, while oxidative stress markers show similarly high prevalence of abnormality in this population 4, 1.
Clinical Implications for Disease Monitoring
Both markers demonstrate similar patterns in disease progression:
CA-125 shows positive correlation with tumor burden and inverse correlation with degree of differentiation, patterns that parallel the relationship between oxidative stress markers and tumor stage 3, 2.
Patients with epithelial ovarian cancer demonstrate decreased preoperative serum levels of SOD and GPX antioxidants alongside increased MDA, findings that associate with advanced tumor stage—the same stages where CA-125 elevation is most pronounced 2.
Important Caveats
CA-125 lacks specificity and can be elevated in benign conditions including endometriosis, pelvic inflammatory disease, and ovarian cysts—conditions that may also involve oxidative stress through inflammatory mechanisms 4, 5.
CA-125 is elevated in only approximately 50% of early-stage (FIGO stage I) ovarian cancer cases, limiting its utility as a screening tool, though oxidative stress markers have not been validated for early detection either 4.
The correlation between CA-125 and oxidative stress does not establish causation; both may be independent consequences of tumor biology rather than one causing the other 1, 2.