Therapy-relevant characteristics

Therapy-relevant characteristics

A therapy decision should be tailored to the individual patient and their cancer as far as possible. Certain substances (targeted tumor therapies) only prove useful, however, if the tumor exhibits certain properties. Breast cancer patients, for example, can receive a treatment with special antibodies, if they are HER2/neu positive. As such, testing on tumor tissue or the primary tumor is already considered routine in modern-day therapy planning. maintrac® can determine therapy-relevant properties through testing carried out directly on the circulating tumor cells in the blood. In this way, maintrac® can help in finding a suitable therapy type, even in situations where the primary tumor has already been surgically removed, or the tumor is inaccessible.

On average, tumor cells have a high rate cell division. During these cell-division cycles, they often change their properties. Surface-properties as well as gene expression or cell DNA within the tumor cells can be affected by these changes. The responsiveness of the tumor cells to the therapy approach used can be affected by these modifications, often meaning that regular maintrac® testing of these properties can have a positive influence on treatment success rate.

In cases of “cancer with unknown primary tumor” various different tests are normally used (e.g. biopsies) to test metastases in order to determine the origin of the primary tumor. Nevertheless, metastases can often be difficult to reach. They do, however, often release cells into the blood, just like the associated primary tumor. The “fluid-biopsy” which examines these cells as part of the maintrac® analysis, contributes to an identification of the primary tumor by determining certain properties of the circulating tumor cells.

Determination of therapy-relevant properties with maintrac®

The following is a list of cell properties that are important when it comes to therapy decisions and that can be determined using the maintrac® method:

Growth factor receptors:
Human epidermal growth factor receptor 2 (Her2/neu)
Epidermal growth factor receptor (EGFR) and EGFR amplification
Vascular endothelial growth factor receptor (VEGFR2)
Insulin-like growth factor 1 receptor (IGF1R)
Stem cell factor receptor (c-Kit)

Prostate-associated markers:
Prostate-specific antigen (PSA)
Prostate-specific membrane antigen (PSMA)

Adhesion markers:
Tissue factor
Thomsen-Friedenreich antigen (TF-antigen)

Others:
Evidence of apoptosis via TUNEL
Antibody-immune reaction against tumor cells (Ig)
Placental alkaline phosphatase (PLAP)
Melan A (Mart-1)

Hormone receptors:
Estrogen receptor (ER)
Progesterone receptor (PR)
Androgen receptor (AR)

Activation and growth markers:
Cell proliferation marker (Ki-67)

Immunomodulatory molecules – new points of attack against cancer:
Programmed death-ligand 1 (PD-L1)
Surface-antigen CD 276 (B7-H3)

The maintrac® lab request form can be found here.

Examples for the importance of therapy-relevant characteristics

For the following targeted therapy types, the CETC/CTC properties play an important role:

  1. Blocking of hormone receptors such as estrogen or androgen receptors
  2. Therapies with antibodies which are targeted against cell-surface molecules, e.g. HER2/neu
  3. Therapies involving so-called “small” molecules which block the signal forwarding of receptors
  4. Determination of the proportion of growing or “dormant” cells, since this also can have an impact on therapy (fast-growing cells are treated with different medications than “dormant”, or very slow-growing, cells)
  5. Determination of the origin of carcinomas of unknown origin (ACUP) by identifying characteristics of circulating tumor cells