title: Serial Serum HER2 Measurements for the Detection of Breast Cancer Recurrence in HER2-Positive Patients.
abstract: OBJECTIVE
  The measurement of serum human epidermal growth factor receptor 2 (HER2) extracellular domain levels is a well-established method for evaluating whether a metastatic HER2-positive breast cancer patient will respond to HER2-targeted treatment. However, little is known about the value of serum HER2 for detecting disease relapse following curative surgical treatment in breast cancer patients. The purpose of this study was to evaluate the sensitivity of serum HER2, carcinoembryonic antigen (CEA), and carcinoma antigen 15-3 (CA 15-3) for the detection of disease recurrence in postoperative breast cancer patients with a primary HER2-positive tumor.
  
  
  METHODS
  Serial measurements were taken of serum HER2, CEA, and CA 15-3 levels in patients with primary invasive HER2-positive breast cancer who underwent curative surgical treatment between January 2008 and December 2010. Following treatment, serum HER2 levels were monitored every 6 months using a chemiluminescence immunoassay.
  
  
  RESULTS
  Overall, 264 patients were analyzed in this retrospective study. The median follow-up period was 27.7 months, and 24 patients relapsed during follow-up. The sensitivity of serum HER2, CEA, and CA 15-3 for the detection of disease recurrence was 37.5%, 25.1%, and 12.5%, respectively. Sensitivity increased to 45.8% when all three tumor markers were combined in the analysis. In a subgroup of patients without liver disease, the sensitivity of serum HER2, CEA, and CA 15-3 was 57.1%, 21.4%, and 14.3%, respectively. Of the 264 patients in this study, 80 patients had chronic hepatitis, liver cirrhosis, or abnormal aspartate aminotransferase or alanine aminotransferase levels during the follow-up period. Following the exclusion of these patients, the sensitivity of serum HER2 for the detection of disease recurrence increased to 57.1%.
  
  
  CONCLUSIONS
  Serial serum HER2 measurement may be useful for the detection of disease relapse in patients with HER2-positive breast cancer. Abnormal liver function can result in elevated serum HER2 in the absence of disease recurrence.
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: June-Hyung
authors.initials: JH
authors.lastname: Ha
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Min-Ki
authors.initials: MK
authors.lastname: Seong
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Eun-Kyu
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Pathology, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Jin Kyung
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Hyesil
authors.initials: H
authors.lastname: Seol
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Ju Young
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Jangmoo
authors.initials: J
authors.lastname: Byeon
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Yeun-Ju
authors.initials: YJ
authors.lastname: Sohn
authors.affiliation: Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Jae Soo
authors.initials: JS
authors.lastname: Koh
authors.affiliation: Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: In-Chul
authors.initials: IC
authors.lastname: Park
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Woo Chul
authors.initials: WC
authors.lastname: Noh
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
authors.forename: Hyun-Ah
authors.initials: HA
authors.lastname: Kim
keywords: Breast neoplasms; Carcinoembryonic antigen; Carcinoma antigen 15-3; Human epidermal growth factor receptor 2; Tumor-associated antigen
references.citation: Science. 1987 Jan 9;235(4785):177-82
references.pmid: 3798106
references.citation: J Clin Oncol. 2007 Nov 20;25(33):5287-312
references.pmid: 17954709
references.citation: Anticancer Res. 2004 May-Jun;24(3b):1987-92
references.pmid: 15274389
references.citation: J Clin Oncol. 1998 Apr;16(4):1340-9
references.pmid: 9552035
references.citation: Int J Biol Markers. 2000 Oct-Dec;15(4):324-9
references.pmid: 11192828
references.citation: Tumour Biol. 1997;18(3):188-96
references.pmid: 9143415
references.citation: Anticancer Res. 1999 Jul-Aug;19(4A):2551-5
references.pmid: 10470193
references.citation: Int J Cancer. 2000 Jul 20;89(4):329-36
references.pmid: 10956406
references.citation: Anticancer Res. 2001 Mar-Apr;21(2B):1465-70
references.pmid: 11396233
references.citation: Biomarkers. 2007 Nov-Dec;12(6):657-67
references.pmid: 17852076
references.citation: Cancer Immunol Immunother. 2004 Mar;53(3):166-75
references.pmid: 14685781
references.citation: Breast Cancer Res Treat. 1995;36(1):41-8
references.pmid: 7579505
references.citation: J Breast Cancer. 2012 Mar;15(1):71-8
references.pmid: 22493631
references.citation: J Gastroenterol. 1994 Oct;29(5):616-20
references.pmid: 7528080
references.citation: Clin Chem. 2006 Mar;52(3):345-51
references.pmid: 16410341
references.citation: Nat Clin Pract Oncol. 2006 May;3(5):269-80
references.pmid: 16683005
references.citation: Clin Chem Lab Med. 2013 Jul;51(7):1511-9
references.pmid: 23403727
references.citation: Scand J Clin Lab Invest Suppl. 1986;181:1-74
references.pmid: 3460162