title: Novel germline CDK4 mutations in patients with head and neck cancer.
abstract: BACKGROUND
  Cyclin-dependent kinase 4 (CDK4) together with its regulatory subunit cyclin D1, governs cell cycle progression through G1 phase. Cyclin-dependent kinase inhibitors, including p16INK4A in turn regulate CDK4. In particular, deregulation of the p16/CDK4/cyclin D1 complex has been established in a variety of human tumors including gliomas, sarcomas, melanoma, breast and colorectal cancer. However, changes in CDK4 have rarely been observed.
  
  
  METHODS
  In this study we used a combination of PCR-SSCP and direct sequencing for mutational screening of CDK4. DNA was isolated from peripheral blood leukocyte of patients with squamous cell carcinoma of head and neck, for screening germline mutations in coding regions of CDK4.
  
  
  RESULTS
  Variations observed in exon 2 and 5 were three missense mutations, g5051G > C (Ser52Thr), g5095G > C (Glu67Gln), g5906C > A, g5907C > G (Pro194Ser) and novel frame shift mutations g7321_23delTGA, g7121_7122insG, g7143delG in exon 7 and 3'UTR respectively.
  
  
  CONCLUSIONS
  In conclusion, two novel mutations were found in N terminal domain which indicates that CDK4 mutation may play a major role in the development and progression of squamous cell carcinoma of head and neck.
authors.affiliation: Cancer Genetics Lab, Department of Biosciences, COMSATS Institute of Information Technology, Park Road Chak shahzad, Islamabad, Pakistan. mkayani@comsats.edu.pk.
authors.forename: Maimoona
authors.initials: M
authors.lastname: Sabir
authors.forename: Ruqia Mehmood
authors.initials: RM
authors.lastname: Baig
authors.forename: Ishrat
authors.initials: I
authors.lastname: Mahjabeen
authors.forename: Mahmood Akhtar
authors.initials: MA
authors.lastname: Kayani