Molecular tumor markers in the blood: early prediction of disease outcome in melanoma patients treated with a melanoma vaccine.

Abstract

Patients with American Joint Committee on Cancer (AJCC) stage III melanoma are at high risk of recurrence and death. We hypothesized that a multiple-marker reverse transcriptase polymerase chain reaction (MM-RT-PCR) blood assay could predict, early in the course of therapy, those patients destined to experience treatment failure with a melanoma vaccine (MV) previously shown to improve survival in a phase II clinical trial. After complete surgical resection, prospectively collected cryopreserved peripheral-blood lymphocyte specimens (n = 90) from the serial bleeds of 30 patients with AJCC stage III melanoma were studied by MM-RT-PCR, using the markers tyrosinase, melanoma antigen recognized by T cells-1 (MART-1), and universal melanoma antigen gene-A (uMAG-A). All patients were enrolled in a phase II MV trial during the period of blood draws, and were selected for this study in a blinded fashion. Median duration of clinical follow-up was 74 months for the 13 survivors and 11 months for the 17 nonsurvivors. The presence of at least one melanoma-specific RT-PCR marker was associated with an increased risk of disease recurrence (risk rate, 3.12; P =.02) and decreased risk of survival (relative rate, 2.62; P =.0496) by multivariate analysis. MM-RT-PCR of the blood provided early prediction of subsequent disease recurrence and death in clinically disease-free AJCC stage III melanoma patients enrolled in a MV phase II trial. On the basis of the results of this pilot study, the MM-RT-PCR blood assay should be considered as a clinically important monitoring tool for assessing patient response to adjuvant therapy, and in the surveillance of clinically disease-free patients for the earliest signs of recurrence.