Is serum HER2 ECD a predictive biomarker for response to trastuzumab in advanced gastric cancer?

Excerpt

Since the ToGA study demonstrated that patients with HER2-positive gastric cancer benefit from trastuzumab in addition to 5-fluorouracil/capecitabine plus cisplatin, trastuzumab is used worldwide with standard chemotherapy. However, not all patients with HER2-overexpressing tumors respond to trastuzumab treatment, and further exploring useful biomarkers is needed. HER2 extracellular domain (ECD) shed into circulation from tumor cells has been reported as a good biomarker for probing HER2 overexpression and monitoring its dynamic change, which reflects a patient’s response to therapy in breast cancer [1]. Recently, Zhou et al. first reported the significant correlation between serum level of HER2 ECD and efficacies of trastuzumab-containing chemotherapy for advanced gastric cancer in the Journal of Gastroenterology [2]. This study is highly impactful to the readership but some points to be discussed seem lacking. …