UC professor makes new breast cancer discovery

In In The News by Barbara Jacoby

By: Patrick Murphy

From: newsrecord.org

Nearly one in eight women will be diagnosed with breast cancer during their lifetime, and each one of these women may have a form of breast cancer radically different from the next.

“That leads to the question, ‘What is breast cancer?’” said Dr. Xiaoting Zhang, associate professor at the Department of Cancer Biology in the University of Cincinnati’s College of Medicine. “Different reasons can lead to different subtypes of breast cancer — it’s not like one thing can answer all of these questions.”

However, a new discovery documented by Zhang’s research team has identified MED1 — an estrogen receptor (ER) binding protein — as a new and important player in the complicated field of cancer biology.

According to Zhang, there are four major subtypes of breast cancer with various alterations in each. However, each of these researched subtypes contain established clues — or biomarkers — which give oncologists an idea of which type of breast cancer each patient has.

These oncologists can then use targeted therapy by administering drugs to neutralize the specific biomarkers which result in the unregulated growth of cancer cells. But, while many breast cancer patients respond to drugs targeting these biomarkers, there are others who don’t respond — a term Zhang describes as “therapy resistant.”

“That’s what leads us into our study,” Zhang said. “We try to figure out what can be used to overcome this kind of resistance.”

Zhang’s study looked at ER+ and ER+/HER2+ subtypes of breast cancers.

Seventy-five percent of all breast cancer patients are categorized as ER+, yet roughly 50 percent of those patients are resistant to the ER targeting drug known as Tamoxifen, according to cancer cell and biology Ph.D. candidate Melissa Leonard, the co-author of this study.

“So, what do you do for these women?” said Sejal Fox, a research scientist and lab manager in UC’s Department of Cancer Biology. “You’ve got no drug that targets that receptor. This is what these guys are doing. Somehow, you’re trying to manipulate the system so that you can have other targets for these poor women who have nothing.”

That other target is MED1, a ER-binding protein that Zhang’s research has not only found in high levels with ER+ and ER+/HER2+, but has shown to contribute to resisting therapeutic drugs such as Tamoxifen.

“If you can degrade this protein, or disrupt its function, you can basically stop the expression of these genes that are allowing these breast cancer cells to grow,” Leonard said.

Leonard said Zhang’s team is working to make MED1 a biomarker like ER or HER2, so that oncologists can add MED1 to their calculus of personally treating each cancer patient.

“That’s called individualized medicine,” Zhang said. “We have these four major types, but in those there are many different types. That’s why we need more people to figure out exactly what pathways went wrong.”

In response to Zhang’s development, a UC accelerated grant is supplying $40,000 to Zhang’s lab for additional safety testing before the research can be moved into clinical trials. However, Zhang said more will be needed to bring this research to cancer patients.

“That’s definitely our goal,” Zhang said. “And if UC wants to invest, that’s certainly very welcome.”