title: Investigation of vasculogenic mimicry in sebaceous carcinoma of the eyelid.
abstract: OBJECTIVE
  Vasculogenic mimicry (VM) is a newly proposed pattern of tumour angiogenesis that has been identified in some malignancies and is associated with poor prognosis. The purpose of this study was to investigate whether sebaceous carcinomas of the eyelid exhibit VM and to determine whether these fluid-conducting patterns are associated with clinicopathologic features, the number of microvessels and the levels of endothelial growth factor (VEGF) and matrix metalloprotease-2 (MMP-2) in tumours.
  
  
  METHODS
  Forty paraffin-embedded samples of sebaceous carcinoma of the eyelid were collected, along with complete clinical and pathologic data for all the cases. Tissue sections were stained for CD34, periodic acid and Schiff (PAS), VEGF and MMP-2. VM was identified by the presence of PAS-positive and CD34-negative loops lined by tumour cells. The VM status of tumour samples was compared with the clinical and pathological data using statistical tests. The levels of VEGF, MMP-2 and the number of microvessels were compared between patients with and without VM.
  
  
  RESULTS
  VM was detected in 14 of 40 (35%) tumour samples. The existence of VM in tumours was associated with tumour size (p=0.007) and recurrence (p=0.021). The number of microvessels was lower in tumours with VM (13.03+/-4.02 versus 22.99+/-7.72; p<0.0001). The staining index of MMP-2 was higher in tumours with VM (27.43, range: 0-5.3) compared to tumours without VM (16.77, range: 0-2.7; p=0.004). However, there was no difference in the expression of VEGF between groups with and without VM (p=0.244).
  
  
  CONCLUSIONS
  Vasculogenic mimicry is present in sebaceous carcinoma of the eyelid making it an unfavourable prognosis sign. MMP-2 is associated with VM formation in sebaceous carcinoma of the eyelid.
authors.affiliation: Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Xu
authors.forename: Renbing
authors.initials: R
authors.lastname: Jia
authors.forename: Yixiong
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xin
authors.initials: X
authors.lastname: Song
authors.forename: Xianqun
authors.initials: X
authors.lastname: Fan
mesh_terms: D018266:Adenocarcinoma, Sebaceous / Q000098:blood supply* / Q000473:pathology; D005142:Eyelid Neoplasms / Q000098:blood supply* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D008833:Microcirculation; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000175:diagnosis* / Q000378:metabolism; D011379:Prognosis; D012626:Sebaceous Gland Neoplasms / Q000098:blood supply* / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D020778:Matrix Metalloproteinase 2