title: [Significance of MEK-ERK cascade in the development of human breast carcinoma].
abstract: OBJECTIVE
  To investigate the MEK and ERK expression and their relationship with clinicopathological parameters in human breast carcinoma, and the effect of preoperative chemotherapy on MEK and ERK protein expression.
  
  
  METHODS
  Samples were obtained from 56 patients with breast carcinoma and 8 patients with benign tumors. Sixteen of the 56 patients received preoperative chemotherapy. Western blot and immunohistochemistry were used to measure the expression of MEK1, MEK2 and ERK1, ERK2 protein.
  
  
  RESULTS
  MEK2 and ERK1, ERK2 protein levels were increased in breast carcinoma tissue compared with those in adjacent normal tissues (t = 7.244, 5.959, 3.735, P < 0.01) and benign tumors (t = 2.206, P < 0.05). The levels of MEK1 were decreased. The expression of MEK2 protein in ER negative patients was higher than that in ER positive ones. MEK2 protein levels were lower in patients who received preoperative chemotherapy than in those who did not.
  
  
  CONCLUSIONS
  Overexpression of MEK-ERK may play an important role in the development of human breast carcinoma. MEK and ERK protein expressions are inhibited by preoperative chemotherapy.
authors.affiliation: Laboratory of Surgical Oncology, Peking University, People's Hospital, Beijing 100044, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Wang
authors.forename: Shan
authors.initials: S
authors.lastname: Wang
authors.forename: Xueguang
authors.initials: X
authors.lastname: Zhu
authors.forename: Jiaqing
authors.initials: J
authors.lastname: Zhang
authors.forename: Xinmin
authors.initials: X
authors.lastname: Qiao
authors.forename: Yingjiang
authors.initials: Y
authors.lastname: Ye
authors.forename: Bin
authors.initials: B
authors.lastname: Liang
authors.forename: Xiangtao
authors.initials: X
authors.lastname: Ma
authors.forename: Zhirong
authors.initials: Z
authors.lastname: Cui
mesh_terms: D000328:Adult; D000368:Aged; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000175:diagnosis / Q000201:enzymology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011379:Prognosis; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism
chemical_list: D011494:Protein Kinases; C482128:MAP2K2 protein, human; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases