Background: Tyrosinase transcripts have been identified in a wide range of normal organs and neoplasms such as cutaneous nevi, breast carcinomas, liposarcomas and schwannomas. The cells responsible for these positive results have not been accurately identified yet, but they might correspond to either fully differentiated melanocytes, melanocytic precursors or cells bearing potential for melanocytic differentiation.
Objective: To assess the expression of tyrosinase mRNA in surgical resection specimens and peripheral blood samples from 2 patients with primary neuroendocrine carcinomas of the skin (PNCS).
Methods: The expression of tyrosinase mRNA transcripts was tested by means of a reverse-transcriptase and nested PCR technique, using specific primers, in tissue samples from surgical specimens and heparinized blood samples from 2 patients with PNCS.
Results: The results of the test were positive in the 2 specimens of PCNS but negative in blood samples.
Conclusion: Our findings provide further support for the hypothesis that PNCS originates from a pluripotent stem cell capable of neuroendocrine cell differentiation, keratin production, and, as reported herein, tyrosinase mRNA expression. It remains to be seen whether this technique can also be applied to patients with PNCS, as an adjunct to staging and treatment planning.