Why HERTEST monitoring?

We are promoting routine monitoring of the serum HER2 biomarker in women with metastatic breast cancer. Your doctor can order HERTEST through her clinic or hospital.  The usefulness of circulating biomarkers in breast cancer management has been studied and debated for years. Most of the attention has focused on CA 15-3 and CA 27.29, which are products of the MUC-1 gene. Serum HER2 is not mentioned in the NCCN guidelines, a preeminent resource for breast cancer management. A review of breast cancer biomarkers published by an ASCO committee in 2007 raised questions about the sHER2/neu test. Those concerns have been resolved by multiple investigators over the intervening years. More recently, monographs and recommendations from an expert AACC panel seem to support serum HER2 monitoring. The consensus of evidence indicates strong prognostic (disease free survival) and predictive (response to therapy) value.

An elevated HERTEST value in the presence of a questionable tissue test  may indicate a HER2 tumor missed by tissue testing. Months or even years later, a tumor originally classified as HER2 negative may give rise to HER2 metastases, and elevated sHER2/neu may be the first clue. Elevated serum HER2, at the time of biopsy or later, carries a poorer prognosis, but the prognosis improves considerably with effective HER2-targeted therapy.


Cancer cells learn how to make the protein PD-L1 to disable white blood cell responsible for native tumor immunity. The soluble form of PD-L1 spills into the blood stream, where it can easily be measured by immunoassay. Soluble PD-L1 has been associated with several cancer, of note, lung and kidney. The CHECKMARK immunoassay will help determine a cancer patient's prognosis and may indicate the efficacy of immunotherapy drugs. Your doctor can order the test through her hospital or clinic.