Enteric bacteria can affect the body's response to cancer treatments

This may explain the uneven treatment results in different patients.

Immunotherapy for cancer treatment has become popular in recent years, a new approach to treating this disease. But this method has a big drawback: unevenness. For some cancer patients, drugs work well with fewer side effects, while others do not see any significant effect.

That's what researchers have tried to understand. A group of scientists recently discovered a link between a patient's response to immune therapy and intestinal bacteria. This study will be presented at an upcoming medical conference.

The team of researchers at MD Anderson Cancer Center (University of Texas) sampled oral and faecal bacteria in 233 patients with melanoma tumors - a type of skin cancer. In this group, 43 patients were on anti-PD-1 therapy - a cancer immunotherapy. Of these 43 people, 30 people with response to treatment and 13 had no progress with treatment with anti-PD-1.

Cancer therapy with anti-PD-1.

People who respond to immunotherapy have some things in common. First, they have a more diverse gut microbiota with a greater density of bacteria called Clostridiales , especially in the family Ruminococcaceae. They also have a higher anti-cancer cell density than the remaining 13 people. Meanwhile, patients who do not respond to treatment, have a Bacteroidales bacterium in their intestines.

It can be said that our immune system is nourished by the types of bacteria we encounter in life. An idea called "hygiene hypothesis" suggests that exposure to earlier bacteria in life can stimulate the immune system for the future. However, the exact way of operation has not been clarified yet. The team is designing to carry out subsequent clinical trials.