Lee CK, et al (2016) J Clin Oncol, Serum human epidermal growth factor 2 extracellular domain as a predictive biomarker for lapatinib treatment efficacy in patients with advanced breast cancer, 34(9):936-944.
Trastuzumab plus paclitaxel or docetaxel in HER-2-negative/HER-2-positive anthracycline- and taxane-refractory advanced breast cancer. Ardavanis A, Kountourakis P, Kyriakou F, Malliou S, Mantzaris I, Garoufali A, Yiotis, I.Scorilas A, Baziotis N, Rigatos G (2008) The Oncologist. 13: 361-369. A study of twenty-two women who had severe progressive disease not responding to conventional cytotoxic chemotherapy. All had a negative tissue test in the past, so they had not received trastuzumab. But all had high sHER2/neu values. Each was treated with trastuzumab plus one of the drugs that had earlier failed. 73% of these patients experienced clinical benefit.
Serum HER-2 predicts response and resistance to trastazumab treatment in breast cancer. Peterson ERB, Sorensen, PD, Jacobsen, EH, Madsen, JS and Brandslund, I, Clin Chem Lab Med (2013) 47:1117-1123. These authors describe decreasing sHER2/neu values greater than 20% during successful Herceptin treatment and rising values in progressive disease.When comparing women judged to be free of disease to women alive with recurrence, there was a dramatic shift in median sHER2/neu values.
Monitoring serum HER2 levels during neoadjuvant trastuzumab treatment within the GeparQuattro trial. Witzel I, Loibl S, von Minckwitz G, Mundhenke C, Huober J, Hanusch C, Henschen S, Hauschild M, Lantzsch T, Tesch H, Latos K, Just M, Hilfrich J, Barinoff J, zu Eulenburg C, Roller M, Untch M, Muller V, Breast Cancer Res Treat (2010) 123:437-445. This paper, summarizes data from a large German trial involving 175 patients. The authors looked at sHER2/neu during neo-adjuvant treatment, when chemotherapy is given before surgery to reduce tumor size and spare breast tissue at surgical removal. Monitoring sHER2/neu was helpful in predicting clinical response. This paper discusses an as yet unresolved issue—some sHER2/neu values in the range of “normal”, maybe as many as half, may still indicate the presence of a HER2 tumor and merit monitoring during treatment.
Human epidermal growth factor 2 (HER2) extracelluar domain levels are associated with progression-free survival in patients with HER2-positive metastatic breast cancer receiving laptinib monotherapy. Lipton A, Leitzel K, Ali SM, Carney W, Platek G, Steplewski K, West P, Lund R, Gagnon R, Martin A, Maltzman J, (2011) Cancer. The most reliable way to evaluate the utility of a sHER2/neu test during treatment is to study women treated with only one HER2-targeted drug. This article evaluated patients receiving only the HER2-targeted drug lapatinib. They observed a greater than 20% fall in sHER2/neu, often as early as four weeks, in patients responding clinically. These doctors, as have others, published very similar results with single drug trastuzumab treatment in a 2008 report. As the number of HER2-targeted drugs increases and the cost of treatment increases, a tool to detect early evidence of drug failure takes on new meaning.