title: Increased expression of L-selectin (CD62L) in high-grade urothelial carcinoma: A potential marker for metastatic disease.
abstract: BACKGROUND
  L-Selectin (CD62L) is a vascular adhesion molecule constitutively expressed on leukocytes with a primary function of directing leukocyte migration and homing of lymphocytes to lymph nodes. In a gene expression microarray study comparing laser-captured microdissected high-grade muscle-invasive bladder cancer (MIBC) without prior treatment and low-grade bladder cancer (LGBC) human samples, we found CD62L to be the highest differentially expressed gene. We sought to examine the differential expression of CD62L in MIBCs and its clinical relevance.
  
  
  METHODS
  Unfixed fresh and formalin-fixed paraffin-embedded human bladder cancer specimens and serum samples were obtained from the University of Connecticut Health Center tumor bank. Tumor cells were isolated from frozen tumor tissue sections by laser-captured microdissected followed by RNA isolation. Quantitative polymerase chain reaction was used to validate the level of CD62L transcripts. Immunohistochemistry and enzyme-linked immunosorbent assay were performed to evaluate the CD62L protein localization and expression level. Flow cytometry was used to identify the relative number of cells expressing CD62L in fresh tumor tissue. In silico studies were performed using the Oncomine database.
  
  
  RESULTS
  Immunostaining showed a uniformly higher expression of CD62L in MIBC specimens vs. LGBCs specimens. Further, CD62L localization was seen in foci of metastatic tumor cells in lymph node specimens from patients with high-grade MIBC and known nodal involvement. Up-regulated expression of CD62L was also observed by flow cytometric analysis of freshly isolated tumor cells from biopsies of high-grade cancers vs. LGBC specimens. Circulating CD62L levels were also found to be higher in serum samples from patients with high-grade metastatic vs. high-grade nonmetastatic MIBC. In addition, in silico analysis of Oncomine Microarray Database showed a significant correlation between CD62L expression and tumor aggressiveness and clinical outcomes.
  
  
  CONCLUSIONS
  These data confirm the expression of CD62L on urothelial carcinoma cells and suggest that CD62L may serve as biomarker to predict the presence of or risk for developing metastatic disease in patients with bladder cancer.
authors.affiliation: Department of Surgery, University of Connecticut Health Center, Farmington, CT.
authors.forename: Dharamainder
authors.initials: D
authors.lastname: Choudhary
authors.affiliation: Department of Pathology, University of Connecticut Health Center, Farmington, CT.
authors.forename: Poornima
authors.initials: P
authors.lastname: Hegde
authors.affiliation: Department of Medicine, University of Connecticut Health Center, Farmington, CT.
authors.forename: Olga
authors.initials: O
authors.lastname: Voznesensky
authors.affiliation: Department of Medicine, University of Connecticut Health Center, Farmington, CT.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Choudhary
authors.affiliation: Department of Cell Biology, University of Connecticut Health Center, Farmington, CT.
authors.forename: Stavros
authors.initials: S
authors.lastname: Kopsiaftis
authors.affiliation: Department of Cell Biology, University of Connecticut Health Center, Farmington, CT.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Claffey
authors.affiliation: Department of Medicine, University of Connecticut Health Center, Farmington, CT.
authors.forename: Carol C
authors.initials: CC
authors.lastname: Pilbeam
authors.affiliation: Department of Surgery, University of Connecticut Health Center, Farmington, CT. Electronic address: jtaylor@uchc.edu.
authors.forename: John A
authors.initials: JA
authors.lastname: Taylor
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D002295:Carcinoma, Transitional Cell / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D019041:L-Selectin / Q000032:analysis / Q000096:biosynthesis*; D061346:Laser Capture Microdissection; D008297:Male; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D016133:Polymerase Chain Reaction; D059467:Transcriptome; D015854:Up-Regulation; D001749:Urinary Bladder Neoplasms / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D019041:L-Selectin
keywords: Bladder cancer; Lymph node; Metastasis; Oncomine