Exploring the prognostic and predictive potential of bacterial biomarkers in non-gastrointestinal solid tumors.

Abstract

Introduction: Standard clinical parameters like tumorsize, age, lymph node status, and molecular markers are used to predictprogression risk and treatment response. However, exploring additional markersthat reflect underlying biology could offer a more comprehensive understandingof the tumor microenvironment (TME). The TME influences tumor development,progression, disease severity, and survival, with tumor-associated bacteriaposited to play significant roles. Studies on tumor-associated microbiota havefocused on high bacterial-load sites such as the gut, oral cavity, and stomach,but interest is growing in non-gastrointestinal (GI) solid tumors, such asbreast, lung, and pancreas. Microbe-based biomarkers, including Helicobacter pylori, humanpapillomavirus (HPV), and hepatitis B and C viruses, have proven valuable inpredicting gastric, cervical, and renal cancers.

Areas covered: Potential of prognostic andpredictive bacterial biomarkers in non-GI solid tumors and the methodologiesused.

Expert opinion: Advances in techniques like 16SrRNA gene sequencing, qPCR, immunostaining, and in situ hybridization have enabled detailed analysis ofdifficult-to-culture microbes in solid tumors. However, to ensure reliableresults, it is critical to standardize protocols, accurately align reads,address contamination, and maintain proper sample handling. This will pave theway for developing reliable bacterial markers that enhance prognosis,prediction, and personalized treatment planning.