CA125 has been regarded as a marker for hyperplastic conditions, such as endometriosis or infectious peritonitis. A high serum CA125 level should therefore be carefully evaluated clinically. We measured CA125 levels in sera and ascites as well as the volume of ascites in patients with ovarian cancer, and also performed immunohistochemical staining of their primary tumors for CA125.
Results: 1. The tumor positive rate for CA125 was 49% immunohistochemically. 2. In the patients whose tumors were positive for CA125, the serum CA125 level was 3,309 U/ml and the ascitic fluid CA125 level was 23,621 U/ml. In the patients whose tumors were negative for CA125 the serum and ascitic fluid levels of CA125 were 264 U/ml and 1,919 U/ml, respectively. Both serum and ascitic fluid CA125 levels were significantly higher in the CA125-positive tumor group than in the CA125-negative tumor group (t-test: both p < 0.05). 3. In both groups, the serum CA125 level increased with advancing stage. 4. There was a positive correlation between the serum CA125 level and the volume of ascites in both groups. CA125-positive tumor group: Y = 1.02X + 0.38, r = 0.90, r2 = 0.81 (p < 0.0001) CA125-negative tumor group: Y = 0.34X + 1.35, r = 0.51, r2 = 0.26 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)