Performance Studies of the New One-Day HER2 IQFISH PharmDx™ – European Multicentre Experience
Magali Lacroix-Triki, David Hardisson, Maria Grazia Tibiletti, Camille Franchet, Frederique Penault-Llorca, Jocelyne Jacquemier, Gaetan Mac Grogan, Laurent Arnould, Tomas Garcia-Caballero, Angel Concha, Giuseppe Viale, Josef Ruschoff. Institut Claudius Regaud, Toulouse, France; University Hospital La Paz, Madrid, Spain; Ospedale di Circolo-University of Insubria, Varese, Italy; Centre Jean Perrin, Clermont-Ferrand, France; Institut Paoli Calmettes, Marseille, France; Institut Bergonié, Bordeaux, France; Centre GF Leclerc, Dijon, France; University Hospital, Santiago de Compostela, Spain; University Hospital Virgen de las Nieves, Granada, Spain; Institute of Oncology and University of Milan, Milan, Italy; Targos Molecular Pathology gmbh, Kassel, Germany
Background: HER2 IQFISH pharmDx™ is a direct fluorescence in situ hybridization (FISH) assay developed with a new non-toxic buffer which reduces hybridization time to only 1-2 hours, enabling a turnaround time of only 3h30min from dewax to counting. We report herein the results of several independent European studies comparing the new IQFISH assay to existing in situ hybridization (ISH) assays.
Design: Comparison studies were independently performed in Germany (one centre), France (five centers), Spain (three centers), Italy (one centre). Cases included in the studies (range, n=27-200) consisted of invasive breast and gastric carcinomas, selected according to HER2 IHC status. HER2 IQFISH pharmDx™ was compared with HER2 FISH (pharmDx™ or PathVysion® HER-2 DNA probe kit) in all studies, Inform Her2 Dual ISH (DISH) (one study) or duoCISH™ (one study). HER2 gene and CEN17 copy number, HER2/CEN17 ratio, staining quality, success rates, handling and workflow were recorded. Among the 4 studies, one was performed on tissue microarrays and several fixatives were tested.
Results: HER2 IQFISH pharmDx™ showed a high level of concordance with FISH (concordance rates from 96.3% to 100%, k=0.914 to 1.00), DISH (96%, k=0.877) or duoCISH™ (94.7%, k=0.875). Failure rates ranged from 2-7% for IQFISH, as compared with 1-9% for FISH, 5% for DISH and 9% for duoCISH™. IQFISH quality was assessed as optimal with brighter nuclei (DAPI), allowing an easy orientation in tissue at low magnification, and more intense red and green signals as compared to FISH. Discordant cases were mainly tumours in the borderline category or so-called polysomic cases, and rarely true heterogeneous tumours.
Conclusions: HER2 IQFISH pharmDx™ is a new high-quality non-toxic assay showing high concordance rates with other in situ hybridization techniques. With a turnaround time of 3½ hours, it improves the workflow and allows a fast HER2 status assessment useful for daily clinical practice and enrollment of patients in targeted clinical trials.
Wednesday, March 6, 2013 9:30 AM
Poster Session V # 261, Wednesday Morning