title: [Cytoplasmic expression of aquaporin-1 in breast cancer cells and its relationship with clinicopathological characteristics and prognosis].
abstract: OBJECTIVE
  To detect the expression of aquaporin 1 (AQP1) in breast cancer tissues, and to analyze its relationship with clinicopathological characteristics and prognosis of breast cancer patients.
  
  
  METHODS
  Histochemical SP staining was used to assess the AQP1 expression in 30 cases of lobular hyperplasia of mammary gland, 16 cases of ductal carcinoma in situ (DCIS), and 78 cases of invasive ductal carcinoma-not otherwise specified (IDC-NOS), and to analyze the relationship between cytoplasmic expression of AQP1 in IDC-NOS and clinical pathological characteristics and prognosis of the patients.
  
  
  RESULTS
  Positive AQP1 immunolabelling appeared as brown deposit over the membrane of myoepithelial cells in all cases of lobular hyperplasia of mammary gland, but only 10.0% of cases showed cytoplasmic staining in glandular epithelial cells. In the ductal carcinoma in situ, brown deposit of AQP1 immunolabelling appeared over the myoepithelial cell membrane in all cases, but only 12.5% of cases were accompanied with cytoplasmic staining in glandular epithelial cells. In the invasive ductal carcinoma not otherwise specified, 35.9% of the cases showed cytoplasmic AQP1 immunoreactivity, but only 3.8% of cases showed positive membrane staining of the tumor cells. There were highly positive AQP1 expression in 14 cases, weakly positive in 14 cases, and negative in 50 cases. Cytoplasmic AQP1 expression in the IDC-NOS cases was significantly correlated with pathologic stage, PR, HER-2, lymph node status, Nottingham prognostic index (NPI) and metastasis or recurrence (all P < 0.05). The 5-year progression-free survival (PFS) rates were 16.8% in the patients with strong positive AQP1 expression, 90.9% in the cases with weakly positive AQP1 expression and 94.9% in the AQP1-negative cases, showing a significant difference (P < 0.05). Multivariate analysis indicated that the lymph node status and cytoplasmic expression of AQP1 were independent factors for PFS (both P < 0.05). The 5-year overall survival (OS) rates were 45.6% in the AQP1- strong positive cases, 90.0% in the AQP1-weakly positive cases and 97.7% in the AQP1-negative cases, showing a significant difference (P < 0.05). Multivariate analysis indicated that the lymph node status and cytoplasmic expression of AQP1 were independent factors affecting the overall survival and progression-free survival (both P < 0.05).
  
  
  CONCLUSIONS
  AQP1 is mainly expressed on the membrane of myoepithelial cells in the benign breast lesions, but in the cytoplasm of breast cancer cells, and its expression is an independent factor affecting prognosis of breast cancer patients.
authors: Department of Breast Pathology, Tianjin Medical University Cancer Hospital (Institute), Key Laboratory of Breast Cancer Prevention and Therapy of the Ministry of Education; Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin, 300060, China.
authors: Bin
authors: B
authors: Zhang
authors: Fang-fang
authors: FF
authors: Liu
authors: Yong-jie
authors: YJ
authors: Ma
authors: Email: fenggumayo@163.com.
authors: Feng
authors: F
authors: Gu
mesh_terms: D000328:Adult; D000368:Aged; D051398:Aquaporin 1 / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism* / Q000473:pathology; D003593:Cytoplasm / Q000378:metabolism*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia / Q000378:metabolism / Q000473:pathology; D008207:Lymphatic Metastasis; D042361:Mammary Glands, Human / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D015996:Survival Rate
chemical_list: D051398:Aquaporin 1; D018719:Erb-b2 Receptor Tyrosine Kinases; D011980:Receptors, Progesterone; C496020:AQP1 protein, human; C508053:ERBB2 protein, human