title: MYC and MXI1 protein expression: potential prognostic significance in women with breast cancer in China.
abstract: OBJECTIVE
  To investigate the expression levels and the clinical significance of MYC and MXI1 proteins in breast cancer.
  
  
  METHODS
  The expression levels of MYC and MXI1 were detected by immunohistochemical assay in 166 cases of breast cancer; the relationships among MYC, MXI1 and the clinicopathological parameters were analyzed by χ2 test. Univariate analysis and Cox's proportional hazards model were used to evaluate the prognostic significance of the 2 proteins.
  
  
  RESULTS
  27.71% of the tumor specimens showed high staining intensity for MYC (high-expression group, HEG-MYC) and 22.89% showed high staining intensity for MXI1 (HEG-MXI1); the expression of 2 proteins was negatively correlated (r = -0.177 p = 0.022). The Kaplan-Meier method for survival analysis showed that patients of the MYC-HEG demonstrated a significantly worse disease-specific survival than those of the MYC-low-expression group (LEG) (χ2 = 11.102, p = 0.001). However, patients of the MXI1-HEG had a significantly better disease-specific survival than those of the MXI1-LEG (χ2 = 7.858, p = 0.005). Both univariate analysis and Cox's proportional hazards model indicated that MYC and MXI1 could be independent prognostic molecular markers.
  
  
  CONCLUSIONS
  MYC-HEG and MXI1-LEG levels are associated with poor prognosis in patients with breast cancer, suggesting that they may be useful molecular markers in breast cancer prognosis prediction.
authors.affiliation: The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
authors.forename: Lin-Ping
authors.initials: LP
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Mai
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Guo
authors.forename: Qing-Xia
authors.initials: QX
authors.lastname: Fan
mesh_terms: D000328:Adult; D000368:Aged; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000378:metabolism* / Q000401:mortality*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D015996:Survival Rate; D016896:Treatment Outcome; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D014408:Biomarkers, Tumor; D016271:Proto-Oncogene Proteins c-myc; D025521:Tumor Suppressor Proteins; C079440:MXI1 protein, human; C489427:MYC protein, human