title: Positive response to trastuzumab in a case of HER2-overexpressing metastatic gastric cancer that presented as severe thrombocytopenia.
abstract: BACKGROUND
  Trastuzumab, a humanized monoclonal antibody directed against human epidermal growth factor receptor 2 (HER2), has been shown to be active against metastatic gastric cancers that overexpress HER2.
  
  
  METHODS
  A 47-year-old man presented with a headache and visual disturbance. He was subsequently found to have an intracranial hemorrhage. Laboratory testing showed severe thrombocytopenia, and a bone marrow biopsy revealed aggregates of malignant tumor cells. Endoscopic biopsy of an ulcerative lesion of the gastric antrum confirmed signet ring cell carcinoma based on the results of H&E staining. Immunohistochemistry of the tumor cells revealed HER2 overexpression with an intensity of 3+, and silver in situ hybridization showed HER2 gene amplification. The patient was treated with trastuzumab because of the presence of severe thrombocytopenia. After 2 months of trastuzumab therapy, gastric wall thickening and ascites were diminished and thrombocytopenia was markedly improved. Trastuzumab was continued for an additional 3 months.
  
  
  CONCLUSIONS
  This is the first report of a positive response to trastuzumab in a patient with HER2-overexpressing metastatic gastric cancer that was accompanied by bone marrow involvement and severe thrombocytopenia. This finding is of considerable relevance for difficult cases of metastatic gastric cancer that preclude the administration of aggressive antineoplastic regimens.
authors: Department of Internal Medicine, Chungbuk National University College of Medicine, Cheongju, Korea.
authors: Jae Hyun
authors: JH
authors: Choi
authors: Hye-Suk
authors: HS
authors: Han
authors: Ho-chang
authors: HC
authors: Lee
authors: Ok-Jun
authors: OJ
authors: Lee
authors: Jeong Tae
authors: JT
authors: Kim
authors: Sung-Nam
authors: SN
authors: Lim
authors: Ki Hyeong
authors: KH
authors: Lee
authors: Seung Taik
authors: ST
authors: Kim
mesh_terms: D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002277:Carcinoma / Q000150:complications / Q000188:drug therapy* / Q000556:secondary*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism; D013921:Thrombocytopenia / Q000209:etiology* / Q000517:prevention & control*; D000068878:Trastuzumab; D016896:Treatment Outcome; D015854:Up-Regulation
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human