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Sights Set on Potential Targeted Treatment for Triple-Negative Breast Cancer

August 5, 2013

Reviewed By Melinda Telli, MD

New research shows triple-negative breast cancer tumors may have high levels of a certain protein in common. Identification of this protein may lead to better understanding of how the cancer grows, and how to more effectively treat it in the future.

Study Background

Triple-negative breast cancer (TNBC) remains one of the least understood forms of the disease, and one of the most challenging to treat. Because it tests negative for estrogen, progesterone and HER2 receptors, TNBC does not respond to the hormonal and targeted therapies available for other breast cancers. Treatment for TNBC can be effective, but relies heavily on surgery, radiation and chemotherapy.

Scientists know that when the mesenchymal-epithelial transition (MET) pathway does not work properly, it may aid in cancer cell growth. The MET pathway is a protein network that, when working normally, helps tell healthy cells when to grow and divide. The researchers explored whether TNBC tumor cells had an unusual amount of MET receptors.

Study Design

The investigators analyzed 170 triple-negative breast cancer tumor samples taken from women during surgery. They studied the number of MET receptors present on the tumor cells and data on the recurrence-free and overall survival of the women. Recurrence-free survival is the length of time before the cancer came back; overall survival is the length of time a woman lived after diagnosis.


Their analysis showed that 89 of the 170 tumors had a high number of MET receptors and that grade three tumors more often had a higher number of MET receptors than tumors of lower grades. A tumor’s grade is a number that predicts how fast it is likely to grow or spread. In breast cancer, grade three is high, meaning the cancer is likely to grow or spread quickly.

Their results also revealed that survival times were shorter in women with tumors that had a high number of MET receptors.

What This Means for You 

These findings will not change your current treatment plan, but they do support the need for more research on the MET pathway and its role in the growth and spread of triple-negative breast cancer cells.

Understanding what pathways are related to cancer cell growth helps scientists identify specific parts of cells that might be targeted by new medicines. Some targeted therapies already exist for receptors like MET that impact other types of breast cancer; knowing more about the MET pathway may eventually lead to targeted therapies for triple-negative breast cancer.

If you have triple-negative breast cancer and are interested in participating in a clinical trial, talk with your doctors about trials that may be open near you or for which you may be eligible. Several trials testing MET inhibitors, medicines that target the MET pathway, are underway and may be recruiting.

NCT01542996, and NCT01575522 are such trials.

For more information on triple-negative breast cancer, read LBBC’s Guide to Understanding Triple-Negative Breast Cancer.

Zagouri, F,Bago-Horvath, Z, Rössler, F, et al. High MET expression is an adverse prognostic factor in patients with triple-negative breast cancer. British Journal of Cancer. 2013;108(5):1100-1105.