In humans, cutaneous melanoblastoma accounts for about 2% of all malignancies and belongs to those tumours whose incidence is worldwide rising steadily over the past few decades. The aim of this study was to examine the group of pigs with advanced melanoblastoma for the presence of circulating neoplastic cells and to assess the applicability of the nested RT-PCR assay for tyrosinase-specific mRNA for studying dissemination of melanoma cells.