Clinical value of combined determination of plasma L-DOPA/tyrosine ratio, S100B, MIA and LDH in melanoma

Aim of the study: L-DOPA/tyrosine ratio (an index of tyrosinase activity), melanoma antigens S100B and MIA, lactate deshydrogenase (LDH) and their combinations were evaluated for clinical value as tumour markers in melanoma. Methods: Blood samples were obtained in 170 melanoma patients (stage I-II: n = 57, III: n = 54, IV. n = 59) at inclusion and in a sub-group of 82 subjects during follow-up for up to 4 years. Laboratory analyses were performed by HPLC (L-DOPA, L-tyrosine), immunoassays (S100B, MIA) and colourimetry (LDH). Results: All markers, except LDH, were elevated in stage IV versus other stages. S100B and MIA highly correlated, especially in stage IV (r(s) : 0.849, p < 0.001). The combination of L-DOPA/tyrosine ratio with S100B displayed the highest sensitivity/specificity (73/70%) to confirm stage III-IV or stage IV alone (69/75%) (ROC optimised cut-off). only the L-DOPA/ tyrosine ratio significantly increased (+36% over 5 months, p = 0.001) during progression from stage I-III to higher stages. S100B, MIA and LDH, but not the L-DOPA/tyrosine ratio, responded to progression towards death in stage IV. All markers exhibited a prognostic value in deceased patients (n = 44); S100B and MIA were the best predictors of survival time by Cox proportional-hazards regression. Conclusion: The combination of plasma L-DOPA/tyrosine ratio and S100B appears an attractive approach for the biological follow-up of melanoma patients. (c) 2007 Elsevier Ltd. All rights reserved.