Monoclonal antibodies MA54 and MA61 as potential reagents in the prognosis of patients with ovarian cancer.

Monoclonal antibodies (moABs) MA54 and MA61 directed to the O-linked NeuAc alpha 2-6GalNAc epitope were generated by immunization with culture supernatants of lung adenocarcinoma cells. We have examined the correlation between the prognosis of patients (overall survival and progression-free survival) and circulating serum levels of CA54/61 antigen by comparison with CA125 in patients with epithelial ovarian cancer. Circulating serum CA54/61 antigen levels were determined by sandwich enzyme immunoassay kits. Serum antigen levels were elevated in 44.4% of the patients. Survival at 3 years for ovarian cancer patients with CA54/61-negative (serum CA54/61 levels < 15.2 U/ml) versus CA54/61-positive (CA54/61 > or = 15.2 U/ml) tumors was 64% versus 25% (P < 0.05). In contrast, there is no significant difference in the prognosis of patients based upon positive or negative CA125 antigen values (51% vs 67%). The overall survival rate was worse in patients with CA54/61-positive sera, indicating that positive CA54/61 levels in serum is an independent predictor of poor prognosis in ovarian cancer. In addition, CA54/61 status has been shown to be associated with early relapse of this malignancy.