UZ Leuven discovers two new subtypes of colorectal cancer

Until now, researchers worldwide have used a model in which they distinguish four types of colon cancer. The research of UZ Leuven has discovered two new subtypes to subdivide colorectal cancer: as expected, half of the intestinal tumors had intestinal mucosal cells, but the other half showed altered mucosal cells that more closely resemble gastric mucosal cells.

The researchers suspect that inflammation is the cause of the change in the mucous membrane cells in the second group. Patients with a tumor from the second group have a less good prognosis: the colorectal cancer shows a very unique growth pattern and very different mutations than those in the first group.

“This is information that is calling into question 30 years of insights into colorectal cancer,” says professor Sabine Tejpar, colorectal cancer researcher at UZ Leuven and KU Leuven. “In a year, the diagnosis for colon cancer will look radically different.”

Hope for treatment

The discovery gives hope for the treatment of colon cancer patients. In contrast to, for example, skin or breast cancer, there is almost no immunotherapy that gives good results in colon cancer. Immunotherapy is possible in barely 10 percent of colorectal cancer patients, more specifically in cancers that have the MSI (microsatellite unstable) property. The researchers found that all MSI colon cancers are in the second recently discovered subgroup. New research must now show whether the other 40 percent intestinal tumors from the second subgroup are also sensitive to immunotherapy.

The study was conducted on more than 60 patient samples from the National Cancer Center Singapore, Singapore General Hospital, Samsung Cancer Center Korea and UZ Leuven.

—