SERUM TYROSINE-HYDROXYLASE ACTIVITY IS INCREASED IN MELANOMA PATIENTS- AN ROC CURVE ANALYSIS

We have studied the serum tyrosine hydroxylase activity of tyrosinase, the key enzyme in the melanogenesis via, as a possible diagnostic fac tor or marker for detection, prognosis and follow-up of patients with melanoma. This activity was determined in 30 melanoma patients (MP) an d in 30 healthy persons (HP) by using a radiometric method. We found m ean values of 10.8 +/- 3.0 and 7.65 +/- 2.32 mU/1 for serum tyrosine h ydroxylase activity in MP and HP, respectively. A very significant inc rease in serum tyrosine hydroxylase activity was observed in MP in com parison to the enzymatic activity in HP (P < 0.00001). Although these data seem very conclusive, we wanted to know whether this test could d iscriminate adequately between MP and HP. In order to reach this aim, a complete statistical study was performed by using receiver operating characteristic (ROC) curve analysis. The cut-off value obtained was 8 .47 mU/1. According to our results and after analytical treatment of t he data, we can confirm that evaluation of tyrosine hydroxylase activi ty in serum could be a quick and reliable diagnostic method for detect ion, prognosis and follow-up in melanoma patients. (C) 1998 Elsevier S cience Ireland Ltd. All rights reserved.