Simultaneous analysis of tyrosinase mRNA and markers of tyrosinase activity in the blood of patients with metastatic melanoma

Determination of blood tyrosinase mRNA by RT-PCR and markers of tyrosinase activity (L-DOPA/L-tyrosine ratio) by HPLC have been proposed as biological tools for the detection of metastases in melanoma patients. We prospective ly evaluated their significance and clinical value in a group of 30 stage I II (n = 10) and IV (n = 20) melanoma patients and one with melanosis of Dub reuilh. L-DOPA/L-tyrosine ratio was elevated in 30% of stage III, 41% of st age IV patients (range: 7.5-261.0 X 10(5)) and in melanosis of Dubreuilh (1 84.8) (reference values: 6-16 X 10(5)). One stage III and four stage IV mel anoma patients were positive for tyrosinase mRNA. In stage IV patients, tyr osinase mRNA positivity was associated with disease progression (P<0.01). T he presence of tyrosinase mRNA in blood is more related to clinical status than level of melanin precursors, which probably reflects tumor burden. (C) 1999 Elsevier Science B.V. All rights reserved.