EVALUATION OF SERUM 5-S-CYSTEINYLDOPA AS A BIOCHEMICAL MARKER OF PROGRESSION OF MALIGNANT-MELANOMA

Serum 5-S-cysteinyldopa (5-S-CD) levels were measured among 30 Japanes e patients with malignant melanoma classified according to the 1987 TN M staging system. Serum 5-S-CD levels were significantly higher in the 30 noma patients than in control subjects (63.5 +/- 179.0 vs 4.3 +/- 1.8 nmol/l). Serum levels were 16.0 +/- 21.7 nmol/l for stages I and I I melanoma, 6.8 +/- 4.8 nmol/l for stage III, and 118.1 +/- 244.7 nmol /l for stage IV. Serum levels were significantly higher in stage IV me lanoma than in stages I + II and stage III. Eleven patients with stage s I, II or III melanoma who underwent curative surgery showed a signif icant decrease in serum 5-S-CD level postoperatively. We believe that serum 5-S-CD level is a useful biochemical marker for determining prog ression of malignant melanoma and evaluating therapeutic effects.