title: Loss of p27KIP1 expression in fully-staged node-negative breast cancer: association with lack of hormone receptors in T1a/b, but not T1c infiltrative ductal carcinoma.
abstract: Nuclear expression of the cell cycle inhibitor p27(KIP1) is reduced in a variety of human malignancies, including breast cancer. Loss of nuclear p27(KIP1) during tumor progression, documented by immunohistochemistry (IHC), has been studied for its potential prognostic implication. We examined by IHC the association between nuclear p27(KIP1) expression and hormone receptor status in T1N0M0 breast cancer.
  
  
  METHODS
  The correlation between nuclear p27(KIP1) expression and estrogen (ER) and progesterone (PR) hormone receptor status was analyzed in 122 human T1N0M0 (68 T1a/b, 54 T1c) breast cancer specimens. All patients were staged as N0 by axillary node dissection.
  
  
  RESULTS
  A statistically significant reduction in p27(KIP1) expression was observed as tumor size increased from T1a/b (7%) to T1c (22%). The proportion of tumors with low nuclear p27(KIP1) expression was higher in the ER-negative/PR-negative group compared to the ER-positive/PR-positive group, but this difference was only statistically significant in the T1a/b subgroup (p=0.0007).
  
  
  CONCLUSIONS
  Further investigations into causes of p27(KIP1) deregulation and their relationship to hormone receptor expression in T1N0M0 breast ductal carcinomas are warranted. Such studies may help identify prognostic, as well as predictive, markers of therapy resistance.
authors.affiliation: New York University School of Medicine and NYU Cancer Institute, New York, NY, USA.
authors.forename: Deepu
authors.initials: D
authors.lastname: Mirchandani
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Roses
authors.forename: Giorgio
authors.initials: G
authors.lastname: Inghirami
authors.forename: Anne
authors.initials: A
authors.lastname: Zeleniuch-Jacquotte
authors.forename: Joan
authors.initials: J
authors.lastname: Cangiarella
authors.forename: Amber
authors.initials: A
authors.lastname: Guth
authors.forename: Rachael Ann
authors.initials: RA
authors.lastname: Safyan
authors.forename: Silvia C
authors.initials: SC
authors.lastname: Formenti
authors.forename: Michele
authors.initials: M
authors.lastname: Pagano
authors.forename: Franco
authors.initials: F
authors.lastname: Muggia
mesh_terms: D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism*; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000096:biosynthesis* / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D014644:Genetic Variation; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D011960:Receptors, Estrogen / Q000096:biosynthesis; D011980:Receptors, Progesterone / Q000096:biosynthesis
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D050760:Cyclin-Dependent Kinase Inhibitor p27