title: Overexpression of Cell Cycle Proteins of Peripheral Lymphocytes in Patients with Alzheimer's Disease.
abstract: OBJECTIVE
  Biological markers for Alzheimer's disease (AD) will help clinicians make objective diagnoses early during the course of dementia. Previous studies have suggested that cell cycle dysregulation begins earlier than the onset of clinical manifestations in AD.
  
  
  METHODS
  We examined the lymphocyte expression of cell cycle proteins in AD patients, dementia controls (DC), and normal controls (NC). One-hundred seventeen subjects (36 AD, 31 DC, and 50 NC) were recruited. The cell cycle proteins CDK2, CDK4, CDK6, cyclin B, and cyclin D were measured in peripheral lymphocytes. Cell cycle protein expression in the three groups was compared after adjusting for age and sex.
  
  
  RESULTS
  The levels of cell cycle proteins CDK2, CDK4, CDK6, cyclin B, and cyclin D were significantly higher in AD patients than in the NC subjects. The DC group manifested intermediate levels of cell cycle proteins compared with the AD patients and the NC subjects. The present study indicates that cell cycle proteins are upregulated in the peripheral lymphocytes of AD patients.
  
  
  CONCLUSIONS
  Cell cycle dysregulation in peripheral lymphocytes may present a promising starting point for identifying peripheral biomarkers of AD.
authors.affiliation: Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Hyeran
authors.initials: H
authors.lastname: Kim
authors.affiliation: Center for Clinical Research, Samsung Biomedical Research Institute, Seoul, Republic of Korea.
authors.forename: Young-Ah
authors.initials: YA
authors.lastname: Kwon
authors.affiliation: Center for Clinical Research, Samsung Biomedical Research Institute, Seoul, Republic of Korea.
authors.forename: Inn Sook
authors.initials: IS
authors.lastname: Ahn
authors.affiliation: Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Sangha
authors.initials: S
authors.lastname: Kim
authors.affiliation: Biostatistics Unit, Samsung Biomedical Research Institute, Seoul, Republic of Korea.
authors.forename: Seonwoo
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan, Republic of Korea.
authors.forename: Sangmee Ahn
authors.initials: SA
authors.lastname: Jo
authors.affiliation: Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.; Center for Clinical Research, Samsung Biomedical Research Institute, Seoul, Republic of Korea.
authors.forename: Doh Kwan
authors.initials: DK
authors.lastname: Kim
keywords: Alzheimer's disease; Biomarker; Cell cycle proteins; Cyclin; Cyclin-dependent kinase; Peripheral lymphocyte