title: Quantitative measurement of HER2 expression in breast cancers: comparison with 'real-world' routine HER2 testing in a multicenter Collaborative Biomarker Study and correlation with overall survival.
abstract: BACKGROUND
  Accurate assessment of HER2 status is critical in determining appropriate therapy for breast cancer patients but the best HER2 testing methodology has yet to be defined. In this study, we compared quantitative HER2 expression by the HERmark™ Breast Cancer Assay (HERmark) with routine HER2 testing by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), and correlated HER2 results with overall survival (OS) of breast cancer patients in a multicenter Collaborative Biomarker Study (CBS).
  
  
  METHODS
  Two hundred and thirty-two formalin-fixed, paraffin-embedded breast cancer tissues and local laboratory HER2 testing results were provided by 11 CBS sites. HERmark assay and central laboratory HER2 IHC retesting were retrospectively performed in a blinded fashion. HER2 results by all testing methods were obtained in 192 cases.
  
  
  RESULTS
  HERmark yielded a continuum of total HER2 expression (H2T) ranging from 0.3 to 403 RF/mm2 (approximately 3 logs). The distribution of H2T levels correlated significantly (P<0.0001) with all routine HER2 testing results. The concordance of positive and negative values (equivocal cases excluded) between HERmark and routine HER2 testing was 84% for local IHC, 96% for central IHC, 85% for local FISH, and 84% for local HER2 status. OS analysis revealed a significant correlation of shorter OS with HER2 positivity by local IHC (HR=2.6, P=0.016), central IHC (HR=3.2, P=0.015), and HERmark (HR=5.1, P<0.0001) in this cohort of patients most of whom received no HER2-targeted therapy. The OS curve of discordant low (HER2 positive but H2T low, 10% of all cases) was aligned with concordant negative (HER2 negative and H2T low, HR=1.9, P=0.444), but showed a significantly longer OS than concordant positive (HER2 positive and H2T high, HR=0.31, P=0.024). Conversely, the OS curve of discordant high (HER2 negative but H2T high, 9% of all cases) was aligned with concordant positive (HR=0.41, P=0.105), but showed a significantly shorter OS than concordant negative (HR=41, P<0.0001).
  
  
  CONCLUSIONS
  Quantitative HER2 measurement by HERmark is highly sensitive, accurately quantifies HER2 protein expression and correlates well with routine HER2 testing. When HERmark and local HER2 results were discordant, HERmark more accurately predicted overall survival.
authors.affiliation: Sarah Cannon Research Institute, 3322 West End Avenue, Nashville, TN, 37203, USA. dyardley@tnonc.com.|Tennessee Oncology, PLLC, 250 25th Avenue North, Nashville, TN, 37203, USA. dyardley@tnonc.com.
authors.forename: Denise A
authors.initials: DA
authors.lastname: Yardley
authors.affiliation: Dartmouth Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, NH, 03766, USA. Peter.A.Kaufman@hitchcock.org.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Kaufman
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. huangw2@labcorp.com.
authors.forename: Weidong
authors.initials: W
authors.lastname: Huang
authors.affiliation: Texas Oncology Bedford, 1615 Hospital Parkway, Bedford, TX, 76022, USA. Lea.krekow@usoncology.com.
authors.forename: Lea
authors.initials: L
authors.lastname: Krekow
authors.affiliation: Texas Oncology and Medical City, 7777 Forest Lane, Dallas, TX, 75230, USA. michael.savin@usoncology.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Savin
authors.affiliation: St. Jude Heritage Medical Group, 2720 Harbor Boulevard, Fullerton, CA, 92835, USA. wlawler@stjoe.org.
authors.forename: William E
authors.initials: WE
authors.lastname: Lawler
authors.affiliation: The Center for Cancer and Hematologic Disease, 1930 New Jersey 70 (East), Cherry Hill, NJ, 08003, USA. ndinubile@centerforcancer.com.
authors.forename: Stephen
authors.initials: S
authors.lastname: Zrada
authors.affiliation: Monroe Medical Associates, 71 Ald Taylor Way, Harvey, IL, 60426, USA. starr.alex@comcast.net.
authors.forename: Alexander
authors.initials: A
authors.lastname: Starr
authors.affiliation: Swedish American Regional Medical Center, 1401 East State Street, Rockford, IL, 61104, USA. rkinnear@swedishamerican.org.
authors.forename: Harvey
authors.initials: H
authors.lastname: Einhorn
authors.affiliation: The West Clinic, 100 N Humphreys Boulevard, Memphis, TN, 38120, USA. lschwartzberg@westclinic.com.
authors.forename: Lee S
authors.initials: LS
authors.lastname: Schwartzberg
authors.affiliation: Arlington Cancer Center, 906 West Randol Mill Road, Arlington, TX, 76012, USA. jadams@acc-tx.com.
authors.forename: John W
authors.initials: JW
authors.lastname: Adams
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. Liey@labcorp.com.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Lie
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. paquet@ipmc.cnrs.fr.|Present address: Institut de Pharmacologie Moléculaire et Cellulaire-IPMC, Sophia Antipolis, 660 Route des Lucioles, 06560, Valbonne, France. paquet@ipmc.cnrs.fr.
authors.forename: Agnes C
authors.initials: AC
authors.lastname: Paquet
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. Sperinj@labcorp.com.
authors.forename: Jeff
authors.initials: J
authors.lastname: Sperinde
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. Mojgan.Haddad@HealthTell.com.|Present address: HealthTell, 3130 Crow Canyon Place, San Ramon, CA, 94583, USA. Mojgan.Haddad@HealthTell.com.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Haddad
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. sanderson@LabCorp.com.
authors.forename: Steve
authors.initials: S
authors.lastname: Anderson
authors.affiliation: Center for Molecular Biology and Pathology, Laboratory Corporation of America, Inc, Research Triangle Park, NC, 27709, USA. Briginm@LabCorp.com.
authors.forename: Marlon
authors.initials: M
authors.lastname: Brigino
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. Rick.L.Pesano@QuestDiagnostics.com.|Present address: Quest Diagnostics, 33608 Ortega Highway, San Juan Capistrano, CA, 92675, USA. Rick.L.Pesano@QuestDiagnostics.com.
authors.forename: Rick
authors.initials: R
authors.lastname: Pesano
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. Michael.Bates@cepheid.com.|Present address: Cepheid, 904 East Caribbean Drive, Sunnyvale, CA, 94089, USA. Michael.Bates@cepheid.com.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Bates
authors.affiliation: Monogram Biosciences, Inc., 345 Oyster Point Boulevard, South San Francisco, CA, 37203, USA. Jodi.Weidler@cepheid.com.|Present address: Cepheid, 904 East Caribbean Drive, Sunnyvale, CA, 94089, USA. Jodi.Weidler@cepheid.com.
authors.forename: Jodi
authors.initials: J
authors.lastname: Weidler
authors.affiliation: Wilshire Oncology Medical Group, 8283 Grove Avenue, Rancho Cucamonga, CA, 91730, USA. lbosserman@coh.org.|Present address: City of Hope, 1500 East Duarte Road, Rancho Cucamonga, CA, 91010, USA. lbosserman@coh.org.
authors.forename: Linda
authors.initials: L
authors.lastname: Bosserman
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism* / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases