title: Immunoglobulin G fragment C receptor polymorphisms and clinical efficacy of trastuzumab-based therapy in patients with HER-2/neu-positive metastatic breast cancer.
abstract: OBJECTIVE
  The anti-HER-2/neu monoclonal antibody trastuzumab has been shown to engage both activatory (fragment C receptor [Fc gamma R]IIIa; Fc gamma RIIa) and inhibitory (Fc gamma RIIb) antibody receptors and Fc gamma R polymorphisms have been identified that may affect the antibody-dependent cell-mediated cytotoxicity (ADCC) of natural-killer cells/monocytes. In this study, we tested whether Fc gamma R polymorphisms are associated with clinical outcome of patients with breast cancer who received trastuzumab.
  
  
  METHODS
  Fifty-four consecutive patients with HER-2/neu-amplified breast cancer receiving trastuzumab plus taxane for metastatic disease were evaluated for genotype for the Fc gamma RIIIa-158 valine(V)/phenylalanine(F), Fc gamma RIIa-131 histidine(H)/arginine(R), and Fc gamma RIIb-232 isoleucine(I)/threonine(T) polymorphisms. Trastuzumab-mediated ADCC of patients' peripheral blood mononuclear cells (PBMCs) was measured by chromium-51 release using a HER-2/neu-expressing human breast cancer cell line as a target. Controls comprised thirty-four patients treated with taxane alone.
  
  
  RESULTS
  Our population was in Hardy-Weinberg equilibrium except for the Fc gamma RIIb polymorphism. The Fc gamma RIIIa-158 V/V genotype was significantly correlated with objective response rate (ORR) and progression-free survival (PFS). Also, there was trend significance in ORR and PFS for the Fc gamma RIIa-131 H/H genotype. The combination of the two favorable genotypes (VV and/or H/H) was independently associated with better ORR and PFS compared with the other combinations. The ADCC analysis showed that V/V and/or H/H PBMCs had a significantly higher trastuzumab-mediated cytotoxicity than PBMCs harboring different genotypes.
  
  
  CONCLUSIONS
  These data support for the first time the hypothesis that Fc gamma R-mediated ADCC plays an important role in the clinical effect of trastuzumab. Prospective studies are needed to confirm the role of Fc gamma R polymorphisms in predicting clinical outcome of patients with breast cancer treated with trastuzumab-based therapy.
authors.affiliation: Medical Oncology Unit, University Hospital of Parma, via Gramsci 14, 43100 Parma, Italy. antoninomusolino@hotmail.com
authors.forename: Antonino
authors.initials: A
authors.lastname: Musolino
authors.forename: Nadia
authors.initials: N
authors.lastname: Naldi
authors.forename: Beatrice
authors.initials: B
authors.lastname: Bortesi
authors.forename: Debora
authors.initials: D
authors.lastname: Pezzuolo
authors.forename: Marzia
authors.initials: M
authors.lastname: Capelletti
authors.forename: Gabriele
authors.initials: G
authors.lastname: Missale
authors.forename: Diletta
authors.initials: D
authors.lastname: Laccabue
authors.forename: Alessandro
authors.initials: A
authors.lastname: Zerbini
authors.forename: Roberta
authors.initials: R
authors.lastname: Camisa
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Bisagni
authors.forename: Tauro Maria
authors.initials: TM
authors.lastname: Neri
authors.forename: Andrea
authors.initials: A
authors.lastname: Ardizzoni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000920:Antibody-Dependent Cell Cytotoxicity / Q000235:genetics; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D018572:Disease-Free Survival; D000077143:Docetaxel; D005260:Female; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D017239:Paclitaxel / Q000008:administration & dosage; D011110:Polymorphism, Genetic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D017452:Receptors, IgG / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D043823:Taxoids / Q000008:administration & dosage; D000068878:Trastuzumab; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000077143:Docetaxel; D017239:Paclitaxel; D018719:Erb-b2 Receptor Tyrosine Kinases; D017452:Receptors, IgG; D043823:Taxoids; D000068878:Trastuzumab