Purpose: There is no consensus regarding the optimal tumor markers for melanoma. We compared 3 tumor markers, TA90-immune complex (TA90IC), melanoma-inhibiting activity (MIA) protein, and S100B protein in Stage III melanoma patients undergoing adjuvant vaccine immunotherapy.
Experimental design: The serum of 75 patients representing 3 prognostic cohorts was assayed for the tumor markers prior to initiating immunotherapy and at 6 follow-up time points. Upper limits of normal for TA90IC, MIA and S100B were set at OD 0.41, 8.5 ng/ml, and 2.5 microg/l, respectively.
Results: At least 1 marker became elevated prior to 41 (80 percent) of 51 recurrences. TA90IC was the earliest elevated marker in 29 (57 percent), MIA in 11 (22 percent), and S100B in 4 (8 percent). Multivariate regression analysis revealed that TA90IC was an independent predictor of survival when elevation occurred between 2 weeks and 3 months, whereas MIA was an independent predictor at 4-6 months. In the poor prognostic cohort, mean values for MIA and S100B increased progressively, whereas TA90IC exhibited a parabolic curve.
Conclusion: In this patient population, TA90IC and MIA were complementary; elevation of the immune complex preceded elevation of the tumor antigen in patients who developed recurrence. Additional studies in populations not receiving vaccine will further clarify the clinical utility of these assays.