title: Her2/neu extracellular domain shedding in uterine serous carcinoma: implications for immunotherapy with trastuzumab.
abstract: BACKGROUND
  We evaluated shedding of epidermal growth factor type II receptor (Her2/neu) extracellular domain (ECD) in primary uterine serous carcinoma (USC) cell lines and in the serum of USC patients and its biological effects in experiments of trastuzumab-induced cytotoxicity in vitro.
  
  
  METHODS
  Her2/neu expression was evaluated by immunohistochemistry (IHC), real-time PCR and flow cytometry, while c-erbB2 gene amplification was assessed using fluorescent in situ hybridisation (FISH). Her2/neu ECD levels in the supernatants of USC cell lines and in the serum of 38 USC patients and 19 controls were tested using ELISA. The biologic effect of Her2/neu ECD on trastuzumab-induced antibody-dependent cell-mediated cytotoxicity (ADCC) was evaluated in 5-h chromium-release assays.
  
  
  RESULTS
  Five out of ten USC cell lines overexpressed Her2/neu by IHC and showed amplification of the c-erbB2 gene. High levels of Her2/neu ECD were found in supernatants of all FISH-positive tumours. In contrast, FISH-negative USC was negative for Her2/neu ECD shedding. Serum Her2/neu ECD levels in patients harbouring 3+Her2/neu tumours were higher than those found in healthy women (P=0.02) or USC patients with 2+ or 1+/negative Her2/neu expression (P=0.02). In cytotoxicity experiments, trastuzumab-mediated ADCC was significantly decreased by the addition of Her2/neu ECD-containing supernatants (P=0.01).
  
  
  CONCLUSIONS
  FISH-positive c-erbB2 USC cell lines shed high levels of Her2/neu ECD. High levels of Her2/neu ECD in USC patients may reduce trastuzumab-mediated ADCC in vitro and potentially neutralise its therapeutic effect in vivo.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, Room 305 LSOG, PO Box 208063, 333 Cedar Street, New Haven, CT, USA.
authors.forename: P
authors.initials: P
authors.lastname: Todeschini
authors.forename: E
authors.initials: E
authors.lastname: Cocco
authors.forename: S
authors.initials: S
authors.lastname: Bellone
authors.forename: J
authors.initials: J
authors.lastname: Varughese
authors.forename: K
authors.initials: K
authors.lastname: Lin
authors.forename: L
authors.initials: L
authors.lastname: Carrara
authors.forename: F
authors.initials: F
authors.lastname: Guzzo
authors.forename: N
authors.initials: N
authors.lastname: Buza
authors.forename: P
authors.initials: P
authors.lastname: Hui
authors.forename: D-A
authors.initials: DA
authors.lastname: Silasi
authors.forename: E
authors.initials: E
authors.lastname: Ratner
authors.forename: M
authors.initials: M
authors.lastname: Azodi
authors.forename: P E
authors.initials: PE
authors.lastname: Schwartz
authors.forename: T J
authors.initials: TJ
authors.lastname: Rutherford
authors.forename: S
authors.initials: S
authors.lastname: Pecorelli
authors.forename: A D
authors.initials: AD
authors.lastname: Santin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000920:Antibody-Dependent Cell Cytotoxicity; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017077:Culture Media, Conditioned; D005260:Female; D005434:Flow Cytometry; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry; D007167:Immunotherapy; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction; D000068878:Trastuzumab; D014594:Uterine Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000628:therapy
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D017077:Culture Media, Conditioned; D000068878:Trastuzumab