Gianna Hammer, PhD, Duke Immunology. Photographed at Jones Building.
Big Ideas

Gianna Hammer, Ph.D.

Before establishing rules of engagement, you must first know your opponent. For Gianna Hammer, Ph.D., that should be a simple task. Her interest lies in gut bacteria and how those organisms cause colon tumors to grow. There are more bacteria in the gut than there are cells in the body. That’s a stat you don’t expect to hear, and we checked with her to make sure it wasn’t a typo. There are TRILLIONS of bacteria in your gut. She has quite a sample to pull from for her study!

We usually think in terms of ‘anti’ when it comes to bacteria – antibacterial hand wash and antibiotics for infection. It feels like we should always try to wash them away or kill them. But, of course, they are there for a reason and get a job done. We actually need bacteria. And we have a system of checks and balances to help. Our immune cells keep them from running amok. There is constantly a battle between the two in our gut, and when the good guys lose too much ground, the effect can sometimes be colorectal cancer.

Hammer’s research could have a significant dual impact on cancer – prevention and treatment. The more we learn about the bacteria, the more opportunity exists that we can sculpt it with dietary changes, thus stopping the tumors from ever even starting to grow.

“Bacteria are always there. When colon tumors grow, we think that gut bacteria force a certain immune cell to make proteins that shield the tumor from attack and help it grow. We are testing these ideas by changing how those immune cells respond to gut bacteria. Our body can fight and kill tumors, and we can help by changing the immune system. We need to understand the bacteria and immune functions,” Hammer said.

Hammer’s research could have a significant dual impact on cancer – prevention and treatment. The more we learn about the bacteria, the more opportunity exists that we can sculpt it with dietary changes, thus stopping the tumors from ever even starting to grow. If you knew the bacteria were working in your favor, you wouldn’t mind so much playing host to a trillion of them, would you?

“Science hasn’t had sequencing tools previously, but that’s changing rapidly. Now we can see all the different kinds of bacteria, the immune cells that respond to this bacteria, and do more studies with rigor. We want to find out which immune cells enter colon tumors, which immune cell’s battle with bacteria cause tumors to grow, and which battle may help fight the tumor,” Hammer added.

We’ve long known about the bacteria that live with us every day. But knowing how the bacteria operates within our immune system could prove to be a game changer for those with colon cancer and those who have a family history of it. Colon and rectal cancers are the second leading cause of cancer death in the U.S.

“Cancers are a growing problem. There should be new ways to respond to them. It’s motivation to tackle this research in ways we haven’t done before,” Hammer said.

Through her research, Hammer could unlock the key to understanding the organisms we can’t even see.