Prolonged survival for melanoma patients with elevated IgM antibody to oncofetal antigen.

Antibody directed against a cultured melanoma cell line known to express an oncofetal antigen was measured in sera obtained from patients with stage II melanomas. This study was undertaken to determine if an inhibiting or enhancing effect on tumor growth would be suggested by a positive or negative correlation of antibody levels with tumor recurrence or patient survival. A positive correlation with disease-free interval and survival was detected among patients who had high levels of the IgM class of antibody before and shortly after surgery for state II disease. The IgG class of antibody over the period measured did not correlate consistently with tumor recurrence. Absorption of the IgM antibody with fetal brain confirmed that the dominant detectable reactivity was directed to the oncofetal antigen. The relevance of these findings is related to that of other evidence indicating that immunity to fetal antigens expressed on tumor cells is a participant in host-tumor interaction.