La Jolla researchers tackle breast cancer

By Lynne Friedmann

Except for skin cancers, breast cancer is the most common cancer among American women.  According to the American Cancer Society, nearly 230,480 women in the United States will be diagnosed with invasive breast cancer this year.

After increasing for more than two decades, female breast cancer incidence rates decreased by about two percent per year from 1999 to 2005. But, given that each year about 39,520 die from breast cancer clearly more needs to be done. Here are highlights of just a few of the ongoing research efforts in Torrey Pines Mesa toward improved diagnosis, treatment, and post-treatment wellness for breast cancer patients.

Using optical imaging

Millions of women over 40 undergo x-ray mammography each year in an effort to detect breast cancer in its early stage, when it is often most treatable. However, traditional mammography involves exposure to radiation and produces poor diagnostic accuracy, resulting in a high rate of false positive diagnoses. UCSD bioengineering grad student Carolyn Schutt and her lab mates Michael Benchimol and Mark Hsu are working on a method to use highly-sensitive light imaging and focused light therapies deep inside the body that will help detect and treat breast cancer more effectively. Known as optical fluorescence imaging, the method could one day offer a safer, less expensive, and more accurate visualization of whether a tumor is present (http://bit.ly/i1GPMo).

Non-surgical approaches

The “sentinel lymph node” is routinely removed and dissected to determine the likelihood that the cancer has spread beyond the breast. However, identifying the correct lymph node to remove is not straightforward. Andrew Goodwin, Ph.D., a postdoctoral fellow in the Department of Nanoengineering in the UCSD Jacobs School of Engineering is studying the use of novel microbubbles with fluorescent outer shells to mark the sentinel lymph node.

The approach involves using ultrasound — high-frequency sound waves used in medical imaging applications — to detect the gas-filled microbubbles injected into a tumor. Once the lymph nodes have been imaged, the radiologist will turn up the power of the ultrasound beam in the area surrounding the sentinel lymph node. This will burst the microbubbles and release non-toxic fluorescent polymer that is designed to stick specifically in the lymph nodes, allowing for a more accurate dissection surgery (

http://bit.ly/gzSSsK

). 

Changing cancer cells

There is growing evidence that some tumors originate from stem cells, which keep proliferating to make more stem cells and give rise to more cancer cells. Robert Oshima, Ph.D., and colleagues at the Sanford-Burnham Medical Institute are looking for drugs that force these cancer stem cells to differentiation. This way, the cells settle down and become a specific cell type that can no longer replicate. This is a very different approach than standard treatments because it doesn’t kill the cells, just forces them to become a different—and benign—cell type (

http://bit.ly/ozIYGU

).

Making treatments better

Erkki Ruoslahti, M.D., Ph.D., and colleagues at Sanford-Burnham are developing peptides that specifically bind cancer cells and the blood vessels that feed them. The peptides do this by following “vascular ZIP codes;” certain cell surface markers that distinguish tumor blood vessels from normal ones. One of these peptides helps co-administered drugs to penetrate deeply into tumor tissue. The peptide has been shown to improve treatment efficacy against human breast cancer (as well as other cancers) in mice, achieving the same therapeutic effect as a normal dose with one-third as much of the drug.

Studying the survivors

There are currently 2.6 million breast cancer survivors in the United States. Researchers at the UCSD Moores Cancer Center are conducting a multi-year study examining risk factors among survivors; among them the effects of weight loss and exercise on recovery. SHAPE (Survivors’ Health and Physical Exercise) is a first-of-its kind program for breast-cancer survivors to offer supervised fitness and nutrition lifestyle modification in an effort to determine its effectiveness in a patient’s vitality and longevity and in preventing cancer recurrence.

Lynne Friedmann is a science writer based in Solana Beach.

   
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