Detection of melanocytes from uveal melanoma in peripheral blood using the polymerase chain reaction

Uveal melanoma is the most common intraocular malignancy in adults and can cause loss of vision in the affected eye and death from metastasis, usually to the liver. The techniques currently used to detect cellular dissemination from the tumor are inadequate, and lack the sensitivity required for the detection of low levels of melanocytes in the peripheral blood of patients. The detection of circulating melanocytes is important as an early indication of the possibility of metastasis.

The viability of reverse transcription/polymerase chain reaction amplification of the tyrosinase gene to detect circulating melanocytes was examined as a first sign of dissemination from uveal melanoma.

It was shown that it is possible to detect as few as ten circulating melanocytes in 5 ml of blood. Blood-borne dissemination was also detected in three of six patients with uveal melanoma examined. Two of these patients had clinically confirmed widespread metastases. A positive result was also recorded in one patient in whom there was no other evidence for tumor dissemination. Overt metastatic disease developed in this patient 9 months after blood collection.

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 the administration of adjuvant therapy.