title: TrkC expression predicts favorable clinical outcome in invasive ductal carcinoma of breast independent of NT-3 expression.
abstract: BACKGROUND
  TrkC, a member of neurotrophin receptor family, functions not only as an oncogene, but also act as a tumor suppressor via a manner of dependence receptor in human malignant tumors. Little is known on the action of TrkC for the clinical prognosis and the progression of breast cancer according to the availability of its ligand NT-3. We sought to investigate the prognostic relevance of NT-3-TrkC axis in breast cancer and estimate its role during the process of breast cancer progression.
  
  
  METHODS
  236 cases of invasive ductal carcinoma (IDC), 60 pure ductal carcinoma in situ (DCIS) and 30 normal breast tissue (NBT) between 2004 and 2005 were included in the study. Spearman's rank correlation test was used to analyze the association of NT-3-TrkC expression and breast cancer progression. The Kaplan-Meier method and Cox proportional hazards model were performed to identify the relevant prognostic factors.
  
  
  RESULTS
  50.4% IDC tumors displayed absent or low TrkC expression, while 49.6% was high TrkC expression. TrkC expression was negatively associated with lymph node metastasis (P = 0.029) and tumor proliferation (P = 0.015). Patients with lower TrkC expressing tumors had a higher risk of recurrence (odds ratio, 0.401; 95% confidence interval, 0.207-0.778; P = 0.007). The layered analysis indicated that patients with high TrkC expression tumors had a favor disease-free survival whether NT-3 and TrkC were co-expressed or solitarily expressed in the tumor (P = 0.000). NT-3 was demonstrated to be not a predictor of IDC patients' prognosis. But NT-3 expression was inversely correlated with the progression of breast cancer (r = -0.341, P = 0.000), since more IDC tumors showed high NT-3 expression than DCIS tumors (51.7% vs. 25.9%), while no NBT showed high NT-3 expression, as well.
  
  
  CONCLUSIONS
  The study indicates TrkC expression reduces tumor relapse independent of NT-3 availability in the IDC. Elevated NT-3 expression contributes to the progression of breast cancer.
authors.affiliation: Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education and Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital and National Clinical Research Center of Cancer West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin 300060, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Nuclear Medicine, Pingjin Hospital, Logistics University of Chinese People's Armed Police Forces Chenglin Road, Hedong District, Tianjin 300162, China.
authors.forename: Zhi-Chun
authors.initials: ZC
authors.lastname: Lin
authors.affiliation: Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education and Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital and National Clinical Research Center of Cancer West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin 300060, China.
authors.forename: Tong-Xian
authors.initials: TX
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education and Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital and National Clinical Research Center of Cancer West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin 300060, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Liu
authors.affiliation: Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education and Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital and National Clinical Research Center of Cancer West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin 300060, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education and Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital and National Clinical Research Center of Cancer West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin 300060, China.
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Liu
authors.affiliation: Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education and Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital and National Clinical Research Center of Cancer West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin 300060, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Niu
keywords: NT-3; TrkC; breast; dependence receptor (DR); invasive ductal carcinoma (IDC); prognosis; progression