Some immune cells in the intestines could initiate cancer, study finds

A subset of white blood cells present in the intestine could lead to cancer, French researchers have found.

A certain kind of white blood cell in the intestine could lead to the development of cancer, according to a new French study. 
Researchers studied a group of immune cells called TH17 lymphocytes, which are present in the intestines, and published their findings in the journal Nature Immunology.
T lymphocytes are a type of white blood cell which directly attack and kill infected cells such as bacteria. The TH17 lymphocytes contribute to intestinal stability, tissue repair, and bacterial protection.
“In the intestine, they have a protective role where they help defend against certain bacteria that live in the intestine or during infection. They also help to keep the intestinal tissue healthy,” Julien Marie, an expert in immunology and the study’s corresponding author, told Euronews Health.
The TH17 lymphocytes have also been associated with inflammatory diseases, such as multiple sclerosis or Crohn’s disease.
Scientists used single-cell RNA sequencing to study the cell population.
“The cells are analysed one by one and not as a group, so we can have the genetic programme of each cell,” Marie explained.
The team discovered eight different subsets of the cells and found that one of them could in certain cases lead to cancer.
Researchers observed a “strong correlation” between people with a high presence of this cell population and patients who develop bowel cancer. They also found that a molecule called TGF beta could inhibit the cells from becoming cancer-causing.
“These tumour-initiating cells derive from normal cells in the body that we all have, normal lymphocytes,” Marie explained.
“And so if there’s no more of this molecule called TGF beta or if its levels decrease in the body, the cells will generate cancer-initiating cells. So this is really the brake put in place by the TGF beta molecule. It really prevents the development of these tumour-initiating cells,” he said.
Nearly 30 per cent of cancers develop as a result of chronic localised inflammation, according to the French National Institute of Health and Medical Research (Inserm).
This discovery could help to improve current cancer treatments, such as immunotherapies that stimulate the immune system to fight cancer.
Stimulating only the good cells that are anti-cancer could help make the immunotherapy more efficient.
“From the clinical point of view of this work, we know that the earlier cancer is detected, the greater the chance of total remission of the cancer and these cells are at the start of the cancer’s development. So, the presence of these cells will alert clinicians that you are at higher risk,” Marie said, which would allow these patients to be provided with a more detailed follow-up.
The study was conducted by researchers from the Claude Bernard University Lyon 1 and the University of Montpellier.