title: [Her2 testing in gastric cancer. What is different in comparison to breast cancer?].
abstract: Based on data from a large multicenter phase III trial (ToGA study) trastuzumab has very recently been approved by the EMEA for metastatic gastric cancer and adenocarcinoma of the gastro-esophageal junction. Only patients with tumors which over express Her2 as defined by IHC2+ and a confirmatory FISH+ result, or IHC 3+, determined by an accurate and validated assay are eligible for trastuzumab therapy. However, testing of Her2 status by immunohistochemistry (IHC) differs from breast cancer in core aspects: 1. IHC2+/3+ is scored even though membranous staining is incomplete if membrane staining is clearly detectable even at low magnification (2.5x/5x, 3+) or medium magnification (10x/20x, 2+). 2. Additionally, membrane staining at the appropriate intensity found in at least 10% of tumor cells is restricted to resection specimens. Evaluation of Her2 in situ hybridization (ISH) is similar to breast cancer with ratio values of > or =2.0 indicating Her2 gene amplification. Taking these modifications into account and defining the HER2 positive subgroup as IHC 3+ and IHC2+/FISH+, approximately 16% of gastric cancers are considered Her2 positive, affecting mainly tumor regions with intestinal (gland forming) type carcinoma. In contrast to breast cancer, up to one-third of gastric cancers show a heterogeneous Her2 status both at IHC and ISH levels which favors bright field ISH over FISH.
authors.affiliation: Pathologie Nordhessen u. Targos GmbH, Germaniastr. 7-9, 34119 Kassel. rueschoff@patho-nordhessen.de
authors.forename: J
authors.initials: J
authors.lastname: Rüschoff
authors.forename: I
authors.initials: I
authors.lastname: Nagelmeier
authors.forename: G
authors.initials: G
authors.lastname: Baretton
authors.forename: M
authors.initials: M
authors.lastname: Dietel
authors.forename: H
authors.initials: H
authors.lastname: Höfler
authors.forename: H U
authors.initials: HU
authors.lastname: Schildhaus
authors.forename: R
authors.initials: R
authors.lastname: Büttner
authors.forename: W
authors.initials: W
authors.lastname: Schlake
authors.forename: O
authors.initials: O
authors.lastname: Stoss
authors.forename: H H
authors.initials: HH
authors.lastname: Kreipe
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D000465:Algorithms; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D005260:Female; D005784:Gene Amplification; D006801:Humans; D017403:In Situ Hybridization; D017404:In Situ Hybridization, Fluorescence; D009362:Neoplasm Metastasis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human