Circulating anti-MUC1 IgG antibodies as a favorable prognostic factor for pancreatic cancer.

MUC1 is immunogenic in vivo and humoral and cellular immune responses against MUC1 have been detected in cancer patients. Our study explored the association of circulating anti-MUC1 antibodies with clinicopathological parameters or patients' survival of pancreatic cancer. Serum specimens from 36 patients with invasive ductal carcinoma of the pancreas were subjected to enzyme immunoassay for anti-MUC1 IgG or IgM antibodies. Serum levels of anti-MUC1 IgG antibodies were significantly correlated with survival time (p = 0.0004), whereas neither those of anti-MUC1 IgM nor anti-Galalpha(1,3)Gal IgG antibodies, the latter known as natural antibodies cross-reactive with MUC1, showed a given tendency. Some patients' sera with the higher antibody titer showed the reactivity with MUC1-transfectants of cultured pancreatic cancer cells, but not with MUC1-negative parental cells. When the samples were tentatively divided into 2 groups by the serum level of anti-MUC1 IgG antibodies, the survival of patients was significantly longer in the group with optical density >or=0.3 than in that with optical density <0.3 (p = 0.008). Circulating anti-MUC1 IgG antibody levels remained significant (HR, 0.03; 95% CI, 0.003-0.289; p = 0.0024) after multivariate analysis for pTNM stage, patient age and gender. These data suggest that circulating anti-MUC1-IgG antibody levels may be predictive for survival of pancreatic cancer patients.