Seventy-three PB samples and 109 BM aspirates from 123 assessable patients with stage II-IV MM were analyzed for tyrosinase mRNA using nested RT-PCR, Twenty-five controls without MM were also evaluated. The RT-PCR results were correlated with overall survival (OS) and clinical stage.

Overall, 23 of the 123 patients with MM (19%) had tyrosinase mRNA in their blood and/or BM, RT-PCR positivity was present in the PB of 9 of 73 patients (12%), whereas 18 of 109 (16.5%) had tyrosinase mRNA in their BM. All controls were tyrosinase PCR negative, There was no correlation between RT-PCR results and clinical stage, Within stage II, BM PCR-positive patients had a shorter median survival (24 months) than BM PCR-negative individuals (median not reached), with a P approaching significance (P = 0.06), There was a statistically significant correlation between blood PCR positivity and decreased overall survival (P = 0.03) in all patients, Blood PCR positivity was associated with a significantly decreased OS in stage II and III (P = 0.01 and 0.02, respectively) and was not a predictor of OS in stage IV, In multivariate analysis, blood RT-PCR for tyrosinase mRNA was found to be an independent predictor of survival (P = 0.03; risk ratio, 2.87),

RT-PCR can specifically detect tyrosinase mRNA in the PB and BM of patients with MM. Blood RT-PCR is an independent predictor of overall survival in stage II-III MM. Additional studies are needed to define the potential role of this assay in the management of patients with advanced melanoma.