Breast Cancer

What is breast cancer?

Breast cancer tumor courtesy of Stallcup lab

Breast cancer is the second most common type of cancer in women. In the U.S. in 2007 (the most recent year for which data is available), 202,964 women were diagnosed with breast cancer and 40,598 women died from the disease, according to the Centers for Disease Control and Prevention. Approximately 12 percent of women in the general population will develop breast cancer sometime during their lives.

The most common types of breast cancer include ductal carcinoma, which begins in the cells that line the milk ducts of the breast, and lobular ductal carcinoma, which originates in the breast lobes.

A variety of genetic and environmental influences can increase a person’s risk of breast cancer. However, some breast cancers are associated with inherited mutations in a few specific genes. The best known are mutations in the genes BRCA1 and BRCA2 (BRCA stands for breast cancer susceptibility gene), which account for five to 10 percent of all breast cancer cases.

Depending on the type of breast cancer and its progression, treatments can include surgery, chemotherapy, radiation therapy, hormone therapy, or targeted therapy aimed specifically at disrupting the molecular underpinnings of the disease.

Breast cancer research at Sanford-Burnham

Sanford-Burnham is home to one of just seven National Cancer Institute (NCI)-designated basic cancer centers in the United States. Researchers in this center aim to preempt cancer before it develops, detect the disease at its earliest point, and eliminate its spread.

Kristiina Vuori, M.D., Ph.D. and
John C. Reed, M.D., Ph.D.

Historically, our scientists have made seminal contributions to breast cancer. Kristiina Vuori, M.D., Ph.D., now director of Sanford-Burnham’s Cancer Center, and others published early findings on cellular communication networks in breast cancer cells. John C. Reed, M.D., Ph.D., now Sanford-Burnham’s CEO, and his laboratory made seminal contributions to the understanding of how certain proteins direct programmed cell death (a process called apoptosis) in breast cancer cells and how these proteins allow breast tumors to resistant chemotherapy.

While many researchers in Sanford-Burnham’s Cancer Center study cellular growth and lifespan—work that impacts almost every type of cancer—our scientists are also pursuing several strategies for finding new treatments that specifically target breast cancer.

Here are a few current breast cancer studies at Sanford-Burnham:

Steering stem cells toward their better nature

Stem cells have the ability to differentiate into many different tissues of the body and play a critical role in regeneration and renewal. Growing evidence suggests that some tumors originate from stem cells. Sanford-Burnham researchers are searching for drugs that will force these errant stem cells to differentiate—that is, settle into a specific type of cell that no longer replicates uncontrollably. Rather than killing cancer cells, this approach would instead coax the stem cells that are driving a patient’s cancer to commit to a benign form.

Read more: Differentiation therapy—a different approach to treating tumors

Giving cancer drugs an address

iRGD

Many treatments for cancer, such as chemotherapy, have serious side effects because they are toxic not only to cancer cells but healthy tissue as well. But what if cancer drugs could be directed to attack only the cancer cells that need killing? Several laboratories at Sanford-Burnham are developing peptides, or short proteins, that specifically bind only to cancer cells and the blood vessels that feed them. These peptides do this by recognizing specific molecular markers—vascular “zip codes”—that are found on tumor blood vessels but not normal vessels. These peptides can be used to direct cancer drugs precisely to the cells that need to be destroyed. One such peptide is called iRGD. When co-administered, iRGD and cancer drugs penetrate deeply into tumors. In mice, iRGD makes cancer drugs more effective, allowing researchers to use lower doses and therefore minimize side effects. Working with a biotechnology company and a major medical center, Sanford-Burnham researchers are now testing iRGD in humans.

Read more: Making cancer treatments better

Short-circuiting breast cancer tumors before they develop

A protein known as MELK is expressed at high levels in breast cancer, and Sanford-Burnham scientists have shown in studies with mice that MELK plays a role in the initiation and progression of mammary tumors. In other genetic experiments, the researchers demonstrated that inhibiting the expression of MELK slows the formation of tumors in mice. Researchers are now trying to learn exactly how MELK drives tumors. They are also searching for chemical inhibitors that might be able to stop the protein—potential precursors to new breast cancer therapies.

Read more: Got MELK?

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Genes and Cancer: Tumor Development
Communications Breakdown: Signal Transduction
Rebuilding Cancer’s Neighborhood: Tumor Microenvironment
Unlocking the Secrets of Cell Death: Apoptosis and Cell Death Research
Breast Cancer