A multimarker real-time RT-PCR for MAGE-A gene expression allows sensitive detection and quantification of the minimal systemic tumor load in patients with localized cancer.

INTRODUCTION: Distant metastases of solid tumors are usually associated with fatal outcome. Disseminated cancer cells are considered early indicators of metastasis. Their sensitive detection and quantification would be a valuable tool for staging of disease and as guidance for therapeutic decisions.

EXPERIMENTAL DESIGN: We established a highly sensitive and quantitative multimarker real-time RT-PCR assay for amplification of cancer-related genes MAGE-A1, -A2, -A3/6, -A4, -A10 and -A12 using SYBR green I to detect one single tumor cell in 2 mL of blood or bone marrow. The feasibility of the assay was tested in a large cohort of 177 patients with locally confined prostate carcinoma.

RESULTS: Analysis revealed frequent MAGE expression in venous blood and bilateral bone marrow samples (25.5% of all cases) and yielded the first quantitative profile of MAGE expression with a broad range of transcript concentrations for individual markers in the minimal systemic tumor load of patients with localized cancer.

CONCLUSIONS: Rare transcripts of different MAGE-A genes can be quantified in clinical samples of cancer patients by a sensitive multimarker real-time RT-PCR. Because of frequent expression of MAGE genes in various types of cancer the multimarker MAGE real-time RT-PCR may be generally useful for detection, quantification and characterization of the individual disseminated tumor load in cancer patients.