title: Expression and prognostic relevance of activated extracellular-regulated kinases (ERK1/2) in breast cancer.
abstract: Extracellular-regulated kinases (ERK1, ERK2) play important roles in the malignant behaviour of breast cancer cells in vitro. In our present study, 148 clinical breast cancer samples (120 cases with follow-up data) were studied for the expression of ERK1, ERK2 and their phosphorylated forms p-ERK1 and p-ERK2 by immunoblotting, and p-ERK1/2 expression in corresponding paraffin sections was analysed by immunohistochemistry. The results were correlated with established clinical and histological prognostic parameters, follow-up data and expression of seven cell-cycle regulatory proteins as well as MMP1, MMP9, PAI-1 and AP-1 transcription factors, which had been analysed before. High p-ERK1 expression as determined by immunoblots correlated significantly with a low frequency of recurrences and infrequent fatal outcome (P = 0.007 and 0.008) and was an independent indicator of long relapse-free and overall survival in multivariate analysis. By immunohistochemistry, strong p-ERK staining in tumour cells was associated with early stages (P = 0.020), negative nodal status (P = 0.003) and long recurrence-free survival (P = 0.017). In contrast, expression of the unphosphorylated kinases ERK1 and ERK2 was not associated with clinical and histological prognostic parameters, except a positive correlation with oestrogen receptor status. Comparison with the expression of formerly analysed cell-cycle- and invasion-associated proteins corroborates our conclusion that activation of ERK1 and ERK2 is not associated with enhanced proliferation and invasion of mammary carcinomas.
authors.affiliation: Institute of Gynecopathology, University Clinics Hamburg-Eppendorf (UKE), Martinistr. 52, Hamburg D-20246, Germany. milde@uke.uni-hamburg.de
authors.forename: K
authors.initials: K
authors.lastname: Milde-Langosch
authors.forename: A-M
authors.initials: AM
authors.lastname: Bamberger
authors.forename: G
authors.initials: G
authors.lastname: Rieck
authors.forename: D
authors.initials: D
authors.lastname: Grund
authors.forename: G
authors.initials: G
authors.lastname: Hemminger
authors.forename: V
authors.initials: V
authors.lastname: Müller
authors.forename: T
authors.initials: T
authors.lastname: Löning
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism*; D018567:Breast Neoplasms, Male / Q000378:metabolism; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism*; D018275:Carcinoma, Lobular / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D010766:Phosphorylation; D011379:Prognosis; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3