Researchers have discovered how an immune system protein, called AIM2 (Absent in Melanoma 2), plays a role in determining the aggressiveness of colon cancer.
Scientists at St. Jude Children's Research Hospital found that AIM2 deficiency causes uncontrolled proliferation of intestinal cells and also discovered that AIM2 influences the microbiota, the population of gut bacteria, apparently fostering the proliferation of "good" bacteria that can protect against colon cancer.
Team leader Thirumala-Devi Kanneganti said that the findings could have important applications for prevention, prognosis and treatment.
Kanneganti added that since reduced AIM2 activity in colorectal cancer patients is associated with poor survival, it might be useful to detect the level of AIM2 expression in polyps taken from colonoscopy and use this as one of the biomarkers for prognosis.
Kanneganti and her team believe that it might be possible to prevent the disease or reduce its risk by treating susceptible people to increase AIM2 activity and give them healthy donor bacteria.
She noted that in people who already have colorectal cancer, therapies that boost the expression of AIM2, such as interferons, might reduce tumor progression. Also, transferring healthy microbiota or a group of "good" bacteria to patients with colorectal cancer at the early stage of disease may prolong survival.
In their experiments with mice, the scientists used chemicals to trigger the process mimicking the development of colorectal cancer. They found that the mice showed drastically reduced AIM2 function, confirming the finding in humans with the cancer. They also found that mice genetically altered to have reduced AIM2 function, when treated with the chemicals, showed significantly more tumors than normal mice.
The study is published in a recent issue of the journal Cell.
