Traditional urinary cytology and tyrosinase RT-PCR in metastatic melanoma patients: correlation with clinical status

Abstract

Background: The finding of a suspicious urinary cytology is not uncommon in melanoma patients, in as much as morphology alone is often unable to distinguish the variable cytologic features of melanoma cells. To date, although tyrosinase RT-PCR assay has been used to identify melanoma cells in peripheral blood and tissues, this method has not been applied until now to the analysis of urine samples.

Methods: RT-PCR mRNA tyrosinase expression was analysed in 79 urine samples from metastatic melanoma patients and correlated to standard morphology/immunocytology. The results were compared to the disease course and presence of genito-urinary involvement.

Results: A positive RT-PCR expression was found in 18/79 urine samples from metastatic patients, 4 of which had positive cytology, 9 atypical and 5 negative. Genito-urinary metastases were demonstrated in 27.8% of tyrosinase positive but in only 9.8% of the negative ones. The majority of positive patients had a progressive disease unresponsive to chemotherapy. Urine samples from 20 non-melanoma cancer patients and 20 healthy subjects were all negative..

Conclusions: Our data demonstrate the higher sensitivity of RT-PCR compared to standard cytology in detection of urinary melanoma cells and suggest that this assay could be used as an additional tool in the presence of negative or suspicious cytology.