Recent studies have illuminated key mechanisms through which bacterial and viral infections may contribute to cancer development and progression, according to a new editorial.
The research revealed multiple pathways through which infections promote cancer development, including inflammation-mediated responses, increased oxidative DNA/RNA damage, suppression of repair mechanisms, and uncontrolled cell proliferation.
"Understanding the infection-mediated cancer programs will help in the development of effective therapeutic interventions and/or preventive vaccine approaches," wrote study authors Ibrahim M. Sayed, PhD, and Soumita Das, PhD, of the University of Massachusetts Lowell in Frontiers in Medicine.
Of particular significance is the role of Helicobacter pylori in cancer development. The editorial detailed how H pylori, a gram-negative bacteria, triggers gastric cancer, colorectal cancer, and extraintestinal cancers through multiple pathways, including upregulation of inflammatory signaling via NF-κB stimulation and increased DNA/RNA oxidative damage.
The investigators also uncovered novel insights about viral contributions to cancer, particularly regarding human papillomavirus (HPV). In one cited study involving 40 colorectal cancer biopsies, 26 samples tested positive for HPV DNA, with HPV16 emerging as the predominant subtype. The virus was also detected in urine samples of HPV-positive patients, suggesting potential new diagnostic approaches.
The editorial highlighted important findings regarding immune cell dynamics in oral cancer development. The investigators showed that depletion of CD8-positive T cells and increased FOXP3-positive regulatory T cells significantly impacted immune homeostasis and tumor progression.
A particularly concerning finding emerged regarding infections in patients with leukemia. While nontuberculous mycobacteria (NTM) infections were relatively rare, occurring in only 0.02% of cases in a study of 29,743 patients, they carried a high mortality rate, underscoring the need for vigilant monitoring.
The investigators discovered potential therapeutic strategies, particularly regarding H pylori vaccination. Current clinical trials are evaluating recombinant vaccines incorporating various antigens including cagA, vacA, ure, babA, sabA, oipA, and porin proteins. However, the editorial noted that "the efficacy of several vaccine types is unknown and most of the research findings are preliminary."
The investigators emphasized the importance of extracellular vesicle connections in cancer development. They noted that outer membrane vesicles of H pylori and host cell–derived extracellular vesicles may mediate the transport of carcinogenic cytotoxins, suggesting potential new therapeutic targets.
The comprehensive review of infection-mediated cancer development highlighted the complex interplay between pathogens and cancer initiation, offering new perspectives on potential therapeutic interventions and preventive strategies.
The editorial was funded in part by NIH grants DK107585 and AG069689, as well as support from the Leona M. and Harry B. Helmsley Charitable Trust. The authors declared having no competing interests.