Abstract
Purpose::
Several studies about tyrosinase-based reverse transcriptase-polymerase chain reaction (RT-PCR) as a method for the detection of circulating melanoma cells in peripheral blood is described in literature,but no long term studies on prognostic impact of tyrosinase PCR in uveal melanoma have yet been reported.To assess the prognostic value of serial reverse transcriptase polymerase chain reaction (RT-PCR) measurements of tyrosinase mRNA in peripheral blood of patients affected with uveal melanoma.
Methods::
Twenty patients (mean age 66+/-, 9 male and 11 female), 12 with medium size melanoma and 8 with large size melanoma, and fiftheen controls (mean age 67 +/-, 10 male and 5 female) affected by serous retinal detachment were selected. RT-PCR for tyrosinase mRNA was performed in each patient before and after treatment and/or surgery.
Results::
In medium size melanoma group, mRNA tyrosinase (pg/µg total RNA) RT-PCR detection was positive in four patients at baseline and in eight after twelve months (p<0.0001). In large size melanoma group three patients results positive at baseline, while five were positive after twelve months (p<0.0001). In the control group mRNA tyrosinase was negative at baseline and after twelve months. Three patients with large melanoma with high levels of mRNA tyrosinase died after eight months. Furthermorere, tyrosinase levels are increased in males, in subject over 60 years, in case of multicentric uveal melanoma, in ciliary body melanoma and in untreated patients with chemiotherapy or immunochemiotherapy.
Conclusions::
Uveal melanoma is a slow growth tumor with poor mitotic and apoptotic activity, in spite of this micrometastases are supposed to be present in a large part of patients at the moment of the diagnosis. Our preliminar study clearly demonstrates the presence of mRNA tyrosinase related to circulating tumoral cells even thou without relation to the total number of circulating cells. Progressive increased marker level are evident in high risk patients particularly in patients with metastatic desease. Further study and follow-up are needed to clarify the role of tyrosinase mRNA as a tumor marker for uveal melanoma.