Tumour microdissemination and survival in metastatic melanoma

The value of tyrosinase messenger RNA (mRNA) detection by reverse-transcrip tase polymerase chain reaction (RT-PCA) as a maker for circulating melanoma cells remains controversial. However it has been suggested that detection of melanoma cell mRNA may be used to evaluate prognosis and disease progres sion in patients with advanced malignant melanoma. We used a highly sensiti ve tyrosinase RT-PCR detection assay to test peripheral blood specimens of 80 patients with metastatic malignant melanoma. Moreover; we developed a mu ltiple marker RT-PCR assay detecting a variety of additional melanocyte/tum our specific markers addressing the potential heterogeneity of gene express ion of circulating melanoma cells, Thus subgroups of 32 and 12 out of all t he 80 patients weve also analysed for multimaker gene expression in their p eripheral blood and bone marrow specimens, respectively. Altogether; 15 out of 80 patients tested positive for one or move molecular markers with hete rogeneous melanocyte/tumour gene expression patterns. All RT- PCR positive patients presented with progressive and widely disseminated disease. We con cluded that the detection of melanoma cell mRNA occurs in a stage of massiv e tumour progression and may predict poor clinical outcome in advanced mali gnant melanoma patients (p<0.001). In addition, the multiple maker RT-PCR a nalysis was more reliable and sensitive than a single molecular marker assa y for the detection of melanoma cells.