V.V. Delektorskaya - Dr.Sc. (Med.), Russian Cancer Research Center of N.N. Blokhin (Moscow) K.V. Orlova - Ph.D. (Med.), Russian Cancer Research Center of N.N. Blokhin (Moscow) L.V. Demidov -Dr.Sc. (Med.), Professor, Russian Cancer Research Center of N.N. Blokhin (Moscow)

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine tumor of skin. Somatostatin receptor (SSTR) different subtypes have been well characterized in human neuroendocrine tumors, but there is no evidence of their expression in MCC. SSTR subtypes 2 and 5 (SSTR2 and SSTR5) expression was studied by immunohistochemical analysis in the tumors of 27 MCC patients. SSTR 2-positivity was detected in 24 of 27 (88.9%) MCC samples as compared to only 4 of 27 (14.8%) for SSTR 5. SSTR2 demonstrated strong membranous immunoreactivity in most primary and metastatic tumors. In contrast, the expression of SSTR5 in MCCs was weak or absent. These results suggest that SSTR2 expression along with other neuroendocrine markers may be additional criteria in morphological diagnosis of this type of tumors. Moreover, SSTR2 expression provides the basis for further studies of somatostatin analog-based diagnostic approaches and potential therapeutic implications for patients with MCC.

 

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