DETECTION OF CIRCULATING NEOPLASTIC-CELLS BY REVERSE-TRANSCRIPTASE POLYMERASE CHAIN-REACTION IN MALIGNANT-MELANOMA - ASSOCIATION WITH CLINICAL STAGE AND PROGNOSIS

Purpose: Circulating melanoma cells can be detected in peripheral bloo d by means of tyrosinase mRNA amplification by reverse-transcriptase p olymerase chain reaction (RT-PCR). We conducted a prospective study to evaluate the clinical significance of the presence of circulating neo plastic cells in the blood of patients with malignant melanoma (MM). M ethods: A sensitive RT-PCR assay was used to detect tyrosinase mRNA in the peripheral blood of patients with stages I to IV melanoma. Health y subjects or patients with other malignancies were used as negative c ontrols. Results: Ninety-one assessable patients were included in the study. There was a statistically significant association between RT-PC R positivity and clinical stage. Circulating melanoma cells were detec ted in 36% of patients with localized disease (stages I and II], in 45 % of patients with regional nodal involvement (stage III), and in 94% of patients with metastatic disease (stage IV) (P < .001). In stage II -III patients who were RT-PCR-positive for mRNA tyrosinase in blood, t he recurrence rate and disease-free survival were significantly worse than patients who were RT-PCR-negative. In multivariate analysis, RT-P CR was an independent prognostic factor for recurrence in patients wit h nonmetastatic disease (P = .002). Conclusion: The detection of circu lating melanoma cells in peripheral blood by RT-PCR correlated with th e clinical stage of patients with melanoma and was an independent prog nostic factor for recurrence. Further studies are warranted to better assess the significance of this test in the evaluation of prognosis, e arly detection of relapse, and in monitoring the effectiveness of syst emic therapy.