DETECTION OF MELANOCYTES FROM UVEAL MELANOMA IN PERIPHERAL-BLOOD USING THE POLYMERASE CHAIN-REACTION

Purpose. Uveal melanoma is the most common intraocular malignancy in a dults and can cause loss of vision in the affected eye and death from metastasis, usually to the liver. The techniques currently used to det ect cellular dissemination from the tumor are inadequate, and lack the sensitivity required for the detection of low levels of melanocytes i n the peripheral blood of patients. The detection of circulating melan ocytes is important as an early indication of the possibility of metas tasis. Methods. The viability of reverse transcription/polymerase chai n reaction amplification of the tyrosinase gene to detect circulating melanocytes was examined as a first sign of dissemination from uveal m elanoma. Results. It was shown that it is possible to detect as few as ten circulating melanocytes in 5 ml of blood. Blood-borne disseminati on was also detected in three of six patients with uveal melanoma exam ined. Two of these patients had clinically confirmed widespread metast ases. A positive result was also recorded in one patient in whom there was no other evidence for tumor dissemination. Overt metastatic disea se developed in this patient 9 months after blood collection. Conclusi ons. The success of this technique has important implications for the detection of circulating tumor cells from uveal melanoma, as an early indication of dissemination. This may be important when considering th e administration of adjuvant therapy.