title: High load of Merkel cell polyomavirus DNA detected in the normal skin of Japanese patients with Merkel cell carcinoma.
abstract: Although Merkel cell polyomavirus (MCPyV) has the potential to cause Merkel cell carcinoma (MCC), it is also found in the normal skin of healthy individuals. However, the mechanism for transformation of MCPyV to an oncogenic form is unknown.
  
  
  
  To investigate the levels of MCPyV infection in the normal skin patients with MCC compared with those in a control cohort.
  
  
  
  We studied a total of six Japanese patients with cutaneous MCC. Sun-exposed and sun-unexposed skin swabs were obtained and analyzed for MCPyV loads using quantitative real-time polymerase chain reaction.
  
  
  
  At first, we found a patient with MCC carrying an extremely high load of MCPyV DNA in normal skin. This unique case prompted us to further explore the levels of MCPyV as skin microbiota in patients with MCC. We showed that MCPyV DNA levels were significantly higher in swabs obtained from normal skin samples of six patients with MCC compared with those from 30 age-matched healthy individuals and 19 patients with other cutaneous cancers. Whereas MCPyV strains obtained from the normal skin of patients with MCC had gene sequences without structural alterations, sequences of the tumor-derived strains showed truncating mutations or deletions.
  
  
  
  Although the number of patients with MCC studied was small, our findings suggest that MCC may occur with a background of high MCPyV load in the skin, and are expected to stimulate further studies on whether such skin virome levels could be one of predictive markers for the development of MCC.
authors.affiliation: Department of Microbiology and Infection, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Hashida
authors.affiliation: Department of Dermatology, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Kimiko
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Department of Dermatology, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakajima
authors.affiliation: Department of Dermatology, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Shiga
authors.affiliation: Department of Microbiology and Infection, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Moe
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Microbiology and Infection, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Masanao
authors.initials: M
authors.lastname: Murakami
authors.affiliation: Department of Microbiology and Infection, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Matsuzaki
authors.affiliation: Department of Pathology, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Naganuma
authors.affiliation: Department of Pathology, Kochi Red Cross Hospital, Kochi, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Kuroda
authors.affiliation: Department of Molecular Biophysics, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Seki
authors.affiliation: Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Harutaka
authors.initials: H
authors.lastname: Katano
authors.affiliation: Department of Dermatology, Kochi Medical School, Kochi University, Kochi, Japan.
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Sano
authors.affiliation: Department of Microbiology and Infection, Kochi Medical School, Kochi University, Kochi, Japan. Electronic address: daibatam@kochi-u.ac.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Daibata
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D015266:Carcinoma, Merkel Cell / Q000821:virology*; D004279:DNA, Viral / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D059965:Merkel cell polyomavirus / Q000235:genetics / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction; D012867:Skin / Q000821:virology*; D012878:Skin Neoplasms / Q000821:virology*; D019562:Viral Load
chemical_list: D004279:DNA, Viral
keywords: Human skin virome; MCPyV genotype; Merkel cell carcinoma; Merkel cell polyomavirus