Hormel Institute researchers have a theory as to why taking aspirin reduces a person’s risk of colorectal cancer.

Researchers led by Executive Director Dr. Zigang Dong and Associate Director Dr. Ann M. Bode, who co-lead the Cellular & Molecular Biology section, discovered aspirin might exert its chemopreventive activity against colorectal cancer, at least partially, by normalizing the expression of epidermal growth factor receptor (EGFR) in gastrointestinal precancerous lesions.

EGFR is overexpressed in about 80 percent of cases involving colorectal cancer, the third-leading cause of cancer-related death in the United States.

Recently published in the open-access journal EBioMedicine, the Institute’s study revealed a previously unknown functional association between EGFR and COX-2 — an enzyme associated with pain and inflammation — during the development of colorectal cancer. The study also provides an explanation as to how taking aspirin can lower the risk of colorectal cancer in patients with familial adenomatous polyposis (FAP), a rare, inherited condition that causes extra tissue (polyps) to form in the large intestine that, if left untreated, almost always becomes cancerous by age 40.

For this study, the Institute partnered with Mayo Clinic researchers who provided tissue sections from recruited FAP patients who were classified as regular aspirin users or nonusers. Consistent clinical trial data strongly suggests that regular use of aspirin and other non-steroidal, anti-inflammatory drugs lowers a person’s lifetime risk of developing colorectal cancer.

This latest research follows another paper published last December in EBioMedicine by the Institute’s Dong/Bode team related to colorectal cancer that provided a promising strategy for preventing and treating the disease. That study showed evidence that the TXA2 pathway also plays an important role in the processes leading to colorectal cancer, and it laid the groundwork for introducing a strategy to target TXA2 for colorectal cancer prevention, early detection and management.

In April, Dong also received a grant for more than $1.7 million over five years from the National Cancer Institute to continue his team’s supercomputer-assisted development of agents that are more effective and less toxic in preventing and treating colorectal cancer.