title: Expression of autophagy-related protein Beclin-1 in malignant canine mammary tumors.
abstract: BACKGROUND
  Autophagy is a self-catabolic mechanism that degrades unnecessary cellular components through lysosomal enzymes. Beclin-1, an autophagy-related protein, establishes the first connection between autophagy and tumorigenesis. The purpose of this study is to assess the Beclin-1 expression pattern and to determine its prognostic significance in patients with malignant canine mammary tumor (CMT).
  
  
  RESULTS
  We examined Beclin-1 expression in 70 cases of malignant CMTs by immunohistochemistry. Cytoplasmic Beclin-1 expression was significantly weaker in cancer cells than in nearby normal mammary glands (p < 0.001). Low cytoplasmic expression (57.14%) was associated with older age, lower degree of tubular formation, increased mitotic activity, higher histologic grade, and extensive necrosis. Low nuclear expression (40%) was connected with older age, lower degree of tubular formation, extensive necrosis, and negative for Her2/neu overexpression. Univariate survival analysis showed that Beclin-1 cytoplasmic expression was a poor prognostic factor for overall survival rate (p < 0.001). Multivariate survival analysis demonstrated that Beclin-1 cytoplasmic expression is an independent prognostic factor (p = 0.016).
  
  
  CONCLUSIONS
  Loss of Beclin-1 is associated with aggressive clinicopathologic features and poor overall survival. The results suggest that Beclin-1 plays an important role in tumor progression of malignant CMTs.
authors.affiliation: Department of Pathology, St. Martin De Porres Hospital, No. 565, Section 2, Daya Road, Chiayi, 60069, Taiwan.
authors.forename: Jing-Lan
authors.initials: JL
authors.lastname: Liu
authors.forename: Kai-Chian
authors.initials: KC
authors.lastname: Chang
authors.forename: Chun-Chih
authors.initials: CC
authors.lastname: Lo
authors.forename: Pei-Yi
authors.initials: PY
authors.lastname: Chu
authors.forename: Chen-Hsuan
authors.initials: CH
authors.lastname: Liu
mesh_terms: D000367:Age Factors; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D002277:Carcinoma / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary; D004283:Dog Diseases / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D005260:Female; D008321:Mammary Glands, Animal / Q000378:metabolism / Q000473:pathology; D015674:Mammary Neoplasms, Animal / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D011379:Prognosis; D012509:Sarcoma / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary; D016019:Survival Analysis
chemical_list: D051017:Apoptosis Regulatory Proteins