Presence of Merkel cell polyomavirus in Japanese cutaneous squamous cell carcinoma.
BACKGROUND
Merkel cell polyomavirus (MCPyV) was first identified in Merkel cell carcinoma (MCC) as a new tumor virus. Studies have also reported differing frequencies of MCPyV detection in other skin cancers in western countries.


OBJECTIVE
Little is known about geographical differences of MCPyV prevalence in non-MCC tumors. We examined the existence of MCPyV in non-MCC skin cancers including squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) in Japanese patients.


METHODS
Paraffin-embedded tissues of cutaneous SCC (n=30) and BCC (n=10) from Japanese patients were tested for the presence of MCPyV by polymerase chain reaction (PCR) with primer sets directed against the genes encoding large-T antigen 3 (LT3) and viral protein 1 (VP1). This was followed by DNA fragment sequencing and immunohistochemistry.


RESULTS
PCR analysis targeting the LT3 gene showed that the viral sequences were found in 4 of 30 (13%) SCC cases. Nested PCR detected the VP1 region in four cases. Sequencing analysis of these PCR-amplified fragments showed a close homology to the previously published MCPyV sequences. Immunohistochemistry with the monoclonal antibody to MCPyV LT-antigen showed positive staining in 2 of 4 LT3 PCR-positive cases. On the other hand, our BCC samples were all negative for MCPyV.


CONCLUSIONS
This study suggested that Japanese cutaneous SCC is infrequently associated with MCPyV. Further worldwide epidemiological surveys are warranted to determine the possible association of MCPyV with pathogenesis of non-MCC skin cancers.
Department of Microbiology and Infection, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan.
Masanao
M
Murakami
Masayuki
M
Imajoh
Takuya
T
Ikawa
Hideki
H
Nakajima
Mikio
M
Kamioka
Yuiko
Y
Nemoto
Takako
T
Ujihara
Jumpei
J
Uchiyama
Shigenobu
S
Matsuzaki
Shigetoshi
S
Sano
Masanori
M
Daibata
D000368:Aged; D000369:Aged, 80 and over; D000957:Antigens, Viral, Tumor / Q000276:immunology; D001483:Base Sequence; D002294:Carcinoma, Squamous Cell / Q000150:complications* / Q000473:pathology / Q000821:virology*; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D018862:Merkel Cells / Q000473:pathology / Q000821:virology*; D008875:Middle Aged; D008969:Molecular Sequence Data; D011120:Polyomavirus / Q000235:genetics / Q000502:physiology*; D027601:Polyomavirus Infections / Q000150:complications* / Q000235:genetics* / Q000821:virology; D016415:Sequence Alignment; D012878:Skin Neoplasms / Q000150:complications* / Q000473:pathology / Q000821:virology*
D000957:Antigens, Viral, Tumor; D004279:DNA, Viral