title: Elements related to heterogeneity of antibody-dependent cell cytotoxicity in patients under trastuzumab therapy for primary operable breast cancer overexpressing Her2.
abstract: Preliminary results from a pilot trial on trastuzumab's mechanism of action against operable breast tumors overexpressing Her2 suggested a role for antibody-dependent cell cytotoxicity (ADCC). To examine factors affecting ADCC intensity and variability, we extended this study to the phenotypic and functional analysis of circulating mononuclear cells in 18 patients. ADCC was induced by trastuzumab therapy in 15 of 18 patients (83%). Inability to develop ADCC in three patients did not depend on inadequate levels of trastuzumab because further increase in its concentration in vitro was ineffective. Rather, susceptibility to develop ADCC was fairly predicted by test with trastuzumab before therapy and was correlated to the number of lymphocytes coexpressing CD16 and CD56. Phenotypic analysis at the end of ADCC evaluating down-regulation of CD16, and up-regulation of CD69 and CD107a, confirmed that natural killer (NK) cells and CD56(+) T cells were involved in productive engagement of trastuzumab. Also, the killing efficiency of CD16(+) lymphocytes was influenced by 158 V/F polymorphism of Fc gamma RIII (CD16), whereas variations of CD247 on NK cells were consistent with trends between ADCC before and after therapy. Complete pathologic response was observed in one patient showing ADCC of outstanding intensity, whereas four cases of partial response showed intermediate ADCC; none of the three patients unable to mount ADCC had significant tumor regression. These data indicate that quantity and lytic efficiency of CD16(+) lymphocytes are major factors for ADCC induction by trastuzumab, and confirm that breast cancer responses to short-term trastuzumab monotherapy may depend on involvement of the ADCC mechanism.
authors: Oncology Department, Scientific Institute of Pavia, Fondazione Salvatore Maugeri-Clinica del Lavoro e della Riabilitazione, Istituti di Ricovero e Cura a Carattere Scientifico, Pavia, Italy.
authors: Stefania
authors: S
authors: Varchetta
authors: Nadia
authors: N
authors: Gibelli
authors: Barbara
authors: B
authors: Oliviero
authors: Elena
authors: E
authors: Nardini
authors: Roberto
authors: R
authors: Gennari
authors: Giovanna
authors: G
authors: Gatti
authors: Luzemira Santos
authors: LS
authors: Silva
authors: Laura
authors: L
authors: Villani
authors: Elda
authors: E
authors: Tagliabue
authors: Sylvie
authors: S
authors: Ménard
authors: Alberto
authors: A
authors: Costa
authors: Francesco F
authors: FF
authors: Fagnoni
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000920:Antibody-Dependent Cell Cytotoxicity / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000235:genetics* / Q000276:immunology* / Q000601:surgery; D005260:Female; D018734:Genes, erbB-2; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D010865:Pilot Projects; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D017452:Receptors, IgG / Q000276:immunology; D000068878:Trastuzumab
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D015703:Antigens, CD; D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D017452:Receptors, IgG; D000068878:Trastuzumab