Expression of HuR in Merkel cell carcinoma and in normal skin.
BACKGROUND
HuR is a ubiquitously expressed member of the Elav/Hu family of mRNA-binding proteins, and its cytoplasmic expression has been recognised to participate in carcinogenesis. The aims of this study were to explore the expression pattern of HuR in primary Merkel cell carcinoma (MCC), lymph node metastases and non-neoplastic skin.


METHODS
Twenty-two primary MCC samples and five lymph node metastases were evaluated for HuR expression by immunohistochemistry. The data were compared with clinical parameters.


RESULTS
Nuclear and cytoplasmic HuR-staining patterns were observed. Nuclear immunoreactivity was observed in 91% of the primary tumors and in 80% of the lymph node metastases. Cytoplasm was positive in 27% of the primary tumors and in 60% of the lymph node metastases. No cytoplasmic HuR immunoreactivity was detected in non-neoplastic skin. However, moderate to strong nuclear staining was found in normal epidermis and in the epithelium of hair follicles and sebaceous glands. Expression of HuR in MCC did not associate with clinicopathological parameters.


CONCLUSIONS
Primary MCCs and their lymph node metastases as well as non-neoplastic skin show nuclear expression of HuR protein. In contrast to non-neoplastic skin, a subset of MCC tumors show cytoplasmic HuR staining, which may contribute to carcinogenesis in MCC.
Koljonen
Virve
V
Department of Plastic Surgery, Helsinki University Hospital, Helsinki, Finland. virve.koljonen@hus.fi
Böhling
Tom
T
Haglund
Caj
C
Ristimäki
Ari
A
D000368:Aged; D000954:Antigens, Surface / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015266:Carcinoma, Merkel Cell / Q000378:metabolism* / Q000556:secondary; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007124:Immunoenzyme Techniques; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D008297:Male; D009363:Neoplasm Proteins / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012867:Skin / Q000033:anatomy & histology / Q000378:metabolism*; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology
D000954:Antigens, Surface; D014408:Biomarkers, Tumor; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D009363:Neoplasm Proteins; D016601:RNA-Binding Proteins