Gut microbiome signature identified in KRAS-mutated colorectal cancer patients
May 2024
According to a recent study published in Microbiology Spectrum, specific microbiome “signatures” were associated with KRAS mutations in patients with colorectal cancer (CRC). These signatures include unique microbiome characteristics such as the presence of specific bacteria, which may serve as a biomarker or indicator for the presence of certain subtypes of CRC, such as KRAS-mutated disease.
KRAS
Approximately 40% of CRCs are KRAS-mutated, which is a prognostic biomarker for lower survival rates and more aggressive tumours.
Prognostic biomarker: a substance such as a protein or DNA that provides information on the likely patient health outcomes.
The gut microbiome
The gut microbiome refers to the trillions of microorganisms including bacteria and fungi that colonize our gastrointestinal system and play an important role in our health. The development of CRC has been linked to dysbiosis or imbalances to the gut microbiome; the connections, however, between gut microbiome imbalances and KRAS-mutations in CRC are not well understood.
The study
Stool samples from 94 patients with CRC were analyzed. 24 patients had KRAS-mutated tumours, and 70 had nonmutated, wild-type KRAS tumours. 26 different types of gut microorganisms were identified in the KRAS-mutated CRC group and not found in the KRAS-wild type group. Bacteria that have been previously linked to the development of CRC, including Fusobacterium, Clostridium, and Shewanella, were all found to be abundant in the microbiomes of patients with KRAS-mutated CRC.
Among patients with nonmutated KRAS CRC, a greater quantity of Bifidobacterium and Akkermansia bacteria were found. These families of bacteria are known to have probiotic effects, promoting a microbiome with more beneficial properties to our health. For example, these types of bacteria are known to suppress pro-inflammatory factors in the colon which can create conditions more favourable to cancer development. The researchers hypothesized that the presence of such probiotic bacteria may reduce a patient’s risk of develop a KRAS mutation and minimize how quickly CRC progresses.
Conclusions
This study findings demonstrate that different CRC genetic mutations and tumour microenvironments may be associated with different gut microbiota. Further research will be conducted with larger patient populations to validate these findings and deepen what is known about the interplay between gut microbiota and colorectal cancer with the hope of developing more targeted treatment options for patients in the future.
