title: The prevalence of Merkel cell polyomavirus in Japanese patients with Merkel cell carcinoma.
abstract: BACKGROUND
  A novel polyomavirus, the Merkel cell polyomavirus (MCPyV) has been implicated in the pathogenesis of Merkel cell carcinoma (MCC); however, the prevalence of MCPyV in Japan has not been extensively investigated.
  
  
  OBJECTIVE
  To clarify the prevalence of MCPyV in Japanese patients with MCC.
  
  
  METHODS
  MCPyV DNA was examined by polymerase chain reaction (PCR) in formalin-fixed paraffin-embedded (FFPE) or frozen tissue samples from 26 patients with MCC diagnosed in four medical centers in Japan. Immunohistochemistry was simultaneously performed using a monoclonal antibody against the viral large T (LT) antigen. FFPE samples from basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) were also analyzed as controls.
  
  
  RESULTS
  Twenty-three out of 26 cases (88.5%) were positive for MCPyV DNA by PCR. The amplified products harbored 4 patterns of mutations. Phylogenetic analysis demonstrated that one of our strains was closely related to the other Japanese strains previously reported. The LT antigen was expressed in various degrees in 20 of 26 cases (76.9%) by immunohistochemistry. Histological type had little relation to CM2B4 positivity, whereas 3 of 5 trabecular-type tumors showed no staining. The immunoreactivity for CM2B4 did not correlate with the relative viral DNA load. In BCC and SCC, the LT antigen was immunohistochemically positive, but MCPyV DNA was not detected by PCR. The cells around some MCC and non-MCC tumors were stained with CM2B4 with a distribution similar to CD20- and CD45RO- (especially CD8-) positive lymphocytes.
  
  
  CONCLUSIONS
  MCPyV was highly positive in Japanese patients with MCC. It is of note that the positive rate differs depending upon the detection method.
authors.affiliation: Department of Dermatology, Gunma University Graduate School of Medicine, Maebashi, Japan. tohatt@gunma-u.ac.jp
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Hattori
authors.forename: Yuko
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Takenouchi
authors.forename: Akiko
authors.initials: A
authors.lastname: Hirofuji
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tsuchida
authors.forename: Takenori
authors.initials: T
authors.lastname: Kabumoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ito
authors.forename: Akira
authors.initials: A
authors.lastname: Shimizu
authors.forename: Etsuko
authors.initials: E
authors.lastname: Okada
authors.forename: Sei-ichiro
authors.initials: S
authors.lastname: Motegi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tamura
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishikawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002280:Basal Cell Carcinoma / Q000208:ethnology / Q000821:virology; D015266:Carcinoma, Merkel Cell / Q000208:ethnology / Q000821:virology*; D002294:Carcinoma, Squamous Cell / Q000208:ethnology / Q000821:virology; D016022:Case-Control Studies; D004279:DNA, Viral / Q000097:blood; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D059965:Merkel cell polyomavirus / Q000235:genetics / Q000302:isolation & purification*; D008875:Middle Aged; D010802:Phylogeny; D027601:Polyomavirus Infections / Q000453:epidemiology* / Q000208:ethnology; D015995:Prevalence; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000208:ethnology / Q000821:virology*; D014412:Tumor Virus Infections / Q000453:epidemiology* / Q000208:ethnology; D019562:Viral Load / Q000235:genetics
chemical_list: D004279:DNA, Viral