title: Clinicopathological significance of dual-specificity protein phosphatase 4 expression in invasive ductal carcinoma of the breast.
abstract: OBJECTIVE
  Dual-specificity protein phosphatase 4 (DUSP4), also known as mitogen-activated protein kinase phosphatase (MKP) 2 is a member of the inducible nuclear MKP group. The role of DUSP4 in cancer development and progression appears to vary with the type of malignancy. The purpose of this study was to investigate DUSP4 expression in a case series of invasive ductal carcinoma of the breast.
  
  
  METHODS
  We constructed tissue microarrays consisting of 16, 14, 47, and 266 cases of normal breast tissue, usual ductal hyperplasia, ductal carcinoma in situ, and invasive ductal carcinoma, respectively. DUSP4 expression was investigated by immunohistochemistry.
  
  
  RESULTS
  Cytoplasmic DUSP4 expression was observed. DUSP4 was more frequently expressed in malignant than in benign cases (p=0.024). The mean DUSP4 expression score was significantly higher in malignant tumors than in benign lesions (p=0.019). DUSP4 expression was significantly correlated with a larger tumor size (>2 cm, p=0.015). There was no significant correlation between overall survival or disease-free survival and DUSP4 expression in all 266 patients. We evaluated the impact of DUSP4 expression on the survival of 120 patients with T1-stage tumors. Interestingly, Kaplan-Meier survival curves revealed that DUSP4 expression had a significant effect on both overall patient survival (p=0.034, log-rank test) and disease-free survival (p=0.045, log-rank test). In early T-stage breast cancer, DUSP4 expression was associated with a worse prognosis.
  
  
  CONCLUSIONS
  DUSP4 is frequently upregulated in breast malignancy, and may play an important role in cancer development and progression. In addition, it may be a marker of adverse prognosis, especially in patients with early T1-stage cancer.
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Hyunsung
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Se Min
authors.initials: SM
authors.lastname: Jang
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Hyein
authors.initials: H
authors.lastname: Ahn
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Jongmin
authors.initials: J
authors.lastname: Sim
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Kijong
authors.initials: K
authors.lastname: Yi
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Yumin
authors.initials: Y
authors.lastname: Chung
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Hulin
authors.initials: H
authors.lastname: Han
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Abdul
authors.initials: A
authors.lastname: Rehman
authors.affiliation: Department of Surgery, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Min Sung
authors.initials: MS
authors.lastname: Chung
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Kiseok
authors.initials: K
authors.lastname: Jang
authors.affiliation: Department of Pathology, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Seung Sam
authors.initials: SS
authors.lastname: Paik
keywords: Breast neoplasms; Dual-specificity phosphatase 4; Prognosis
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