title: Estrogen, progesterone, and HER2/neu receptor discordance between primary and metastatic breast tumours-a review.
abstract: Discordance in estrogen (ER), progesterone (PR), and HER2/neu status between primary breast tumours and metastatic disease is well recognized. In this review, we highlight how receptor discordance between primary tumours and paired metastasis can help elucidate the mechanism of metastasis but can also effect patient management and the design of future trials. Discordance rates and ranges were available from 47 studies (3384 matched primary and metastatic pairs) reporting ER, PR, and HER2/neu expression for both primary and metastatic sites. Median discordance rates for ER, PR, and HER2/neu were 14 % (range 0-67 %, IQR 9-25 %), 21 % (range 0-62 %, IQR 15-41 %), and 10 % (range 0-44 %, IQR 4-17 %), respectively. Loss of receptor expression was more common (9.17 %) than gain (4.51 %). Discordance rates varied amongst site of metastasis with ER discordance being highest in bone metastases suggesting that discordance is a true biological phenomenon. Discordance rates vary for both the biomarker and the metastatic site. Loss of expression is more common than gain. This can affect patient management as it can lead to a reduction in both the efficacy and availability of potential therapeutic agents. Future studies are recommended to explore both the mechanisms of discordance as well as its impact on patient outcome and management.
authors.affiliation: Division of Surgical Oncology, University of Ottawa, Ottawa, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Yeung
authors.affiliation: Division of Medical Oncology, Department of Medicine, Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, Canada.|Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Hilton
authors.affiliation: Division of Medical Oncology, Department of Medicine, Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, Canada.|Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Clemons
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Mazzarello
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Hutton
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Haggar
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: C L
authors.initials: CL
authors.lastname: Addison
authors.affiliation: Division of Medical Oncology, Department of Medicine, Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, Canada.
authors.forename: I
authors.initials: I
authors.lastname: Kuchuk
authors.affiliation: Division of Medical Oncology, Department of Medicine, Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, Canada.
authors.forename: X
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Division of Medical Oncology, British Columbia Cancer Agency, University of British Columbia, Vancouver, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Gelmon
authors.affiliation: Division of Surgical Oncology, University of Ottawa, Ottawa, Canada. anarnaout@toh.on.ca.|Ottawa Hospital Research Institute, Ottawa, Canada. anarnaout@toh.on.ca.
authors.forename: A
authors.initials: A
authors.lastname: Arnaout
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology* / Q000628:therapy; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D058990:Molecular Targeted Therapy; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000235:genetics / Q000378:metabolism*; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone
keywords: Breast cancer; Estrogen receptor; Her2/neu; Metastasis; Progesterone receptor