title: Molecular analysis of the p27/kip1 gene in breast cancer.
abstract: BACKGROUND
  Genetic polymorphisms and mutations of the genes involved in tumorigenesis may determine individual susceptibility for cancer. The p27/Kip1 protein belongs to the family of cyclin-dependent kinase-inhibitory proteins, which are negative regulators of cell-cycle progression. Reduced protein levels of p27/Kip1 have been reported in numerous human cancers including breast cancer.
  
  
  RESULTS
  p27 gene mutations and the codon 109 polymorphism were investigated in breast cancer patients by single strand conformation polymorphism analysis, PCR-restriction fragment length polymorphism analysis and DNA sequencing. Mutations were identified in 2 of 24 breast tumor samples. One G-->A transition resulting in a silent mutation and a single base deletion resulting in a nonsense mutation were detected in one patient. Another breast cancer sample harbored a T-->A transition at codon 159. An association between the codon 109 B allele and breast cancer was observed.
  
  
  CONCLUSIONS
  Our study indicates that mutational alterations in the p27 gene are rare in human breast cancer. The codon 109 B allele is associated with high-grade tumors.
authors.affiliation: Department of Medical Biology, Cerrahpaşa Medical School, Istanbul University, Istanbul, Turkey.
authors.forename: Hatice
authors.initials: H
authors.lastname: Tigli
authors.forename: Nur
authors.initials: N
authors.lastname: Buyru
authors.forename: Nejat
authors.initials: N
authors.lastname: Dalay
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D050760:Cyclin-Dependent Kinase Inhibitor p27; D015536:Down-Regulation; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D018807:Polymorphism, Single-Stranded Conformational
chemical_list: C436291:CDKN1B protein, human; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27