title: High prevalence of human cytomegalovirus in brain metastases of patients with primary breast and colorectal cancers.
abstract: BACKGROUND
  Brain metastases (BMs) develop by largely unknown mechanisms and cause major morbidity and mortality in patients with solid tumors. Human cytomegalovirus (HCMV) is frequently detected in tumor tissue from patients with different cancers. Here, we aimed to determine the prevalence and potential prognostic role of HCMV in BMs.
  
  
  METHODS
  We obtained archived samples of BMs from 41 patients with breast cancer and 37 with colorectal cancer and paired primary tumor tissues from 13 and 12 patients in each respective group. In addition, primary breast cancer tissues from 15 patients were included. HCMV proteins were detected with an immunohistochemical technique and Western blot. HCMV nucleic acids were detected with TaqMan polymerase chain reaction (PCR) assay.
  
  
  RESULTS
  HCMV proteins were abundantly expressed in 99% of BM specimens, and in 12 of 13 (92%) paired primary breast cancer specimens. All 12 paired colon cancer samples were positive for HCMV proteins. Protein staining was mainly confined to neoplastic cells. Western blot analysis detected an HCMV-IE reactive protein in 53% of breast cancer specimens, and PCR detected the presence of HCMV DNA and transcripts in 92% and 80% of samples, respectively. Patients with high-level expression of HCMV-IE proteins in their tumors had a shorter time to tumor progression and shorter overall survival.
  
  
  CONCLUSIONS
  The prevalence of HCMV proteins and nucleic acids is very high in primary and metastatic tumors and may drive the development of metastatic brain tumors; therefore, this virus may represent a potential therapeutic target in metastatic cancer.
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden.
authors.forename: Chato
authors.initials: C
authors.lastname: Taher
authors.affiliation: Clinical Epidemiology Unit, Karolinska University Hospital, Stockholm, Sweden; Department of Oncology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Frisk
authors.affiliation: Department of Oncology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Stina
authors.initials: S
authors.lastname: Fuentes
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden.
authors.forename: Piotr
authors.initials: P
authors.lastname: Religa
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Costa
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden.
authors.forename: Alice
authors.initials: A
authors.lastname: Assinger
authors.affiliation: Department of Breast and Endocrine Surgery, Department of Surgery, Akershus University Hospital, Oslo, Norway.
authors.forename: Katja Kannisto
authors.initials: KK
authors.lastname: Vetvik
authors.affiliation: Department of Breast and Endocrine Surgery, Department of Surgery, Akershus University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Ida R K
authors.initials: IR
authors.lastname: Bukholm
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden.
authors.forename: Koon-Chu
authors.initials: KC
authors.lastname: Yaiw
authors.affiliation: Clinical Epidemiology Unit, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Karin Ekström
authors.initials: KE
authors.lastname: Smedby
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Bäcklund
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden. Electronic address: cecilia.naucler@ki.se.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Söderberg-Naucler
authors.affiliation: Unit of Experimental Medicine (L8:03), Center for Molecular Medicine, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden. Electronic address: afsar.rahbar@ki.se.
authors.forename: Afsar
authors.initials: A
authors.lastname: Rahbar