title: Aberrant expression of cyclin E in low-risk node negative breast cancer.
abstract: BACKGROUND
  Cyclin E is a cell cycle regulatory protein which occurs in G1, peaks in late G1 and is degraded in early S-phase. Cyclin E overexpression appears to be an independent prognostic factor for overall survival in breast cancer. Nuclear cyclin A is a reliable marker for S-and G2-phases. Consequently, aberrant expression of cyclin E can be detected by simultaneous immunostainings for cyclin A and cyclin E. Studies have shown that aberrant cyclin E might provide additional prognostic information compared to that of cyclin E alone. This study aimed to investigate cyclin E and aberrant cyclin E expression in low-risk node negative breast cancer.
  
  
  METHODS
  We compared women that died from their breast cancer (n=17) with women free from relapse > 8 years after initial diagnosis (n=24). All women had stage I, low risk breast cancer. The groups were matched regarding tumour size, receptor status, adjuvant chemotherapy and tumour differentiation. Tumour samples were analysed regarding expression of cyclin A, cyclin E and double-stained tumour cells using immunoflourescence staining and digital microscopy.
  
  
  RESULTS
  No differences were seen regarding expression of cyclin E or aberrant cyclin E in cases compared to controls.
  
  
  CONCLUSIONS
  We conclude that neither cyclin E nor aberrant cyclin E is a prognostic factor in low-risk node negative breast cancer patients.
authors.affiliation: Department of Oncology, Radiology and Clinical Immunology, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Ahlin
authors.forename: Bettina
authors.initials: B
authors.lastname: Gruhne
authors.forename: Marit
authors.initials: M
authors.lastname: Holmqvist
authors.forename: Anders
authors.initials: A
authors.lastname: Zetterberg
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Fjällskog
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000556:secondary; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000556:secondary; D016022:Case-Control Studies; D019925:Cyclin A / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D005500:Follow-Up Studies; D006801:Humans; D009367:Neoplasm Staging; D015513:Oncogene Proteins / Q000378:metabolism*; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012307:Risk Factors; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; C475820:CCNE1 protein, human; D019925:Cyclin A; D019927:Cyclin E; D015513:Oncogene Proteins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone