A study suggests that attaching a radioactive tag to the targeted therapy Herceptin (chemical name: trastuzumab) might allow researchers to monitor how HER2-positive breast cancer cells respond to Herceptin treatment. These results were reported at the 2010 American Association for Cancer Research annual meeting.
This type of tagged Herceptin is called radiolabeled conjugated trastuzumab by researchers. Tagging a medicine with a radioactive substance is called radioistope labeling.
The researchers tracked the tagged Herceptin with a PET (positron emission tomography) scan. Tagging the Herceptin didn't change the medicine's ability to treat HER2-positive breast cancer.
HER2-positive cancers make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that encourage breast cancer cells to grow and spread. About one out of every four breast cancers is HER2-positive.
Herceptin works by blocking the HER2 protein's ability to make HER2-positive breast cancers grow by attaching to the HER2 receptors on breast cancer cells. So tracking the number of cancer cells that have tagged Herceptin attached to them and figuring out much Herceptin is in the tumor could be a good way to see if the treatment is working. Using tagged Herceptin to monitor the cancer also might help answer questions about whether more treatment, chemotherapy for example, makes sense.
This study was done in a lab with mice, not on people. While the results are promising, more research is needed so doctors understand the safety and usefulness of this monitoring technique in women diagnosed with breast cancer.
Stay tuned to Breastcancer.org's Research News to learn about new results that might help doctors develop new breast cancer treatments and better use the treatments we have now.