Colorectal cancer ranks as the fourth most prevalent cancer in the UK and is the second leading cause of cancer-related fatalities. Recent research offers promising insights that could enhance clinicians' understanding of the disease's progression, its potential aggressiveness, and patients' responses to various treatments.
A team of researchers conducted a comprehensive analysis using whole genome sequencing (WGS) data from over 9,000 cancer patients. Their findings, published in Science Translational Medicine, challenge the long-standing belief that each cancer type possesses a unique microbial signature.
"This study reshapes our understanding of the role of microbes in cancer," stated Dr. Abraham Gihawi, the lead researcher from UEA's Norwich Medical School.
Unveiling Tumor Microbes
To achieve their results, the researchers utilized Genomics England DNA sequence data from 11,735 cancer samples across 22 diverse cancer types.
"Collecting cancer DNA sequences also provides insights from the microbial DNA within these samples," explained Dr. Gihawi. "We aimed to determine the specific DNA composition of microbes in each sample, developing software to eliminate human DNA and focus on the microbial DNA."
They then correlated this microbial data with clinical information regarding cancer types and patient outcomes.
The results contradicted previous assertions that each cancer type has a distinct microbiological fingerprint. Notably, colorectal cancer stood out, exhibiting a unique and identifiable microbial community.
"Our findings indicate that only colorectal tumors harbor distinct microbial communities," Dr. Gihawi added. "These microbial signatures were so precise that they could differentiate colorectal tumors from others, potentially aiding in more accurate diagnoses and further research into the microbes associated with colorectal cancer."
The study also highlighted broader implications. In oral cancers, specific viruses like HPV (human papillomavirus) were detected more accurately than with current diagnostic methods. Additionally, rare yet hazardous viruses, such as Human T-Lymphotropic Virus-1 (HTLV-1), which can remain dormant, were identified as potential contributors to cancer development.
Microbial Influence on Survival and Treatment Response
The research suggests that microbes may play a role beyond mere coexistence with cancer. In some instances, they appear linked to patient survival rates.
"We discovered that certain bacteria correlated with poorer survival rates in specific sarcoma cases, prompting potential avenues for further research and treatment options," remarked Dr. Gihawi. "Excitingly, in some sarcoma cases, specific bacteria were associated with improved survival rates, indicating that microbes could eventually help physicians predict treatment responses and inspire new therapeutic strategies."
The Role of Whole Genome Sequencing in Medicine
Experts emphasize the increasing significance of genome sequencing in contemporary healthcare. Prof. Daniel Brewer from UEA's Norwich Medical School commented, "This study underscores the clinical value of whole genome sequencing in identifying pathogens like HTLV-1 and papillomavirus that might otherwise remain undetected."
"By uncovering hidden infections and offering insights into cancer prognosis--especially in sarcomas--genomic analysis is emerging as an essential tool in precision medicine," he added.
Collaboration and Support
The project was spearheaded by UEA, involving collaboration from various institutions, including the University of Leeds, the Quadram Institute, and the Institute of Cancer Research in London. Funding was generously provided by the Big C Cancer Charity and Prostate Cancer UK.