PRIMARY NEUROENDOCRINE CARCINOMA OF THE SKIN EXPRESSES TYROSINASE MESSENGER-RNA - DETECTION BY A SPECIFIC NESTED PCR TECHNIQUE

Background: Tyrosinase transcripts have been identified in a wide rang e of normal organs and neoplasms such as cutaneous nevi, breast carcin omas, liposarcomas and schwannomas, The cells responsible for these po sitive results have not been accurately identified yet, but they might correspond to either fully differentiated melanocytes, melanocytic pr ecursors or cells bearing potential for melanocytic differentiation. O bjective: To assess the expression of tyrosinase mRNA in surgical rese ction specimens and peripheral blood samples from 2 patients with prim ary neuroendocrine carcinomas of the skin (PNCS). Methods: The express ion of tyrosinase mRNA transcripts was tested by means of a reverse-tr anscriptase and nested PCR technique, using specific primers, in tissu e 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: Ou r findings provide further support for the hypothesis that PNCS origin ates from a pluripotent stem cell capable of neuroendocrine cell diffe rentiation, keratin production, and, as reported herein, tyrosinase mR NA expression. It remains to be seen whether this technique can also b e applied to patients with PNCS, as an adjunct to staging and treatmen t planning.