Study of the measurement of serum extracellular domain of HER-2/neu protein with CLIA method.
OBJECTIVE
Immunohistochemistry (IHC) and Fluorescent In Situ Hybridization (FISH) are important technologies to examine the protein expression and gene amplification of human epidermal growth factor receptor type 2/neu (HER-2/neu), respectively, in breast cancer tumors; however, tumor samples are not always available for examination. Therefore, an easy and sensitive examination to detect HER2-overexpressed tumors should be developed. The extracellular domain of HER-2/neu protein (HER2ECD) has been reported to be observed in the serum of many patients with metastatic breast cancer. In this study we assessed the clinical usefulness of serum HER2ECD (sHER2ECD) as a biological marker in breast cancer.


METHODS
We measured sHER2ECD levels in 108 patients with breast cancer using the ADVIA Centaur assay system, and conventional tumor markers, i.e. CEA and CA15-3, using enzyme or chemiluminescent immunoassay. The sHER2ECD levels were compared with the levels of tumor markers and clinical characteristics.


RESULTS
Patients with primary breast cancer who had four or more lymph nodes involved (n=6) showed significantly higher sHER2ECD values than those with no nodes involved (n=57, p<0.05) and those with 1 to 3 nodes involved (n=15, p<0.01). In the IHC-positive group, the positive rate of sHER2ECD was higher than those of CA15-3 or CEA. In metastatic breast cancer, the combination of sHER2ECD and CA15-3 showed the highest positive rate (81.5%). In all 3 patients with HER2-overexpressed cancer showing a partial response (PR) or complete response (CR) to trastuzumab therapy, sHER2ECD levels declined after treatment (39.9 to 58.7%).


CONCLUSIONS
The sHER2ECD assay by the CLIA method may be useful for the diagnosis and monitoring of metastatic/recurrent breast cancer.
Kuroda
Noriyuki
N
Department of Clinical Laboratory, Kagawa University Hospital, Kita gun, Kagawa-pref. 761-0793, Japan. nkuroda@med.kagawa-u.ac.jp
Kontani
Keiichi
K
Kajikawa
Tatsushi
T
Taminato
Tomohiko
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000097:blood*; D012680:Sensitivity and Specificity; D000068878:Trastuzumab
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab