Mokuyasu Seiichi, Suzuki Yasuhiro, Seto Takayuki, Miyachi Hayato, Tokuda Yutaka
Department of Clinical Laboratory, Tokai University Hospital, Japan.
Rinsho Byori. 2012 Jul;60(7):612-20.
The human epidermal growth factor receptor type 2 (HER2) protein has been used as a biomarker for breast cancer. A new method based on chemiluminescent immunoassay for measuring the serum levels of the extracellular domain of HER2 protein (sHER2-ECD) has been developed. Its clinical usefulness has not been clearly established. We studied the clinical usefulness of sHER2-ECD in monitoring breast cancer patients.
We examined the clinical effectiveness of sHER2-ECD using the ADVIA Centaur XP System in comparison with conventional tumor markers (CA15-3 and CEA) in 148 patients with breast cancer with or without trastuzumab treatment.
The positive rate for sHER2-ECD, CA15-3, and CEA in trastuzumab patients (36) was 25.0%, 19.4%, and 16.7%, and that in non-trastuzumab patients (112) was 20.5%, 22.3%, and 22.3%, respectively. Twenty-three out of 112(20.5%) non-trastuzumab patients were found positive for sHER2-ECD in spite of the negative IHC. Measurement of sHER2-ECD and CA15-3 showed no difference in the expression profile among different clinical stages. During long-term observation in patients negative for HER2 protein by immunohistochemistry, sHER2-ECD was found to be a relatively sensitive indicator of metastasis to distant organs, such as liver and bone, as compared with CA15-3.
sHER2-ECD testing may be a useful tumor marker for monitoring breast cancer patients, even in those with negative IHC for the HER2 protein.
人表皮生长因子受体2（HER2）蛋白已被用作乳腺癌的生物标志物。一种基于化学发光免疫分析的新方法已被开发用于测量血清中HER2蛋白细胞外结构域（sHER2-ECD）的水平。其临床实用性尚未明确确立。我们研究了sHER2-ECD在监测乳腺癌患者中的临床实用性。
我们使用ADVIA Centaur XP系统检测了148例接受或未接受曲妥珠单抗治疗的乳腺癌患者中sHER2-ECD与传统肿瘤标志物（CA15-3和CEA）相比的临床有效性。
曲妥珠单抗治疗患者（36例）中sHER2-ECD、CA15-3和CEA的阳性率分别为25.0%、19.4%和16.7%，未接受曲妥珠单抗治疗患者（112例）中的阳性率分别为20.5%、22.3%和22.3%。112例（20.5%）未接受曲妥珠单抗治疗的患者中，尽管免疫组化结果为阴性，但有23例sHER2-ECD检测呈阳性。sHER2-ECD和CA15-3的检测在不同临床分期的表达谱上没有差异。在免疫组化检测HER2蛋白为阴性的患者长期观察中，发现与CA15-3相比，sHER2-ECD是远处器官（如肝脏和骨骼）转移的相对敏感指标。
sHER2-ECD检测可能是监测乳腺癌患者的有用肿瘤标志物，即使是那些HER2蛋白免疫组化结果为阴性的患者。
