Blood-based biomarkers in gastrointestinal cancers

Gastrointestinal (GI) cancers account for approximately 35% of all cancer-related deaths worldwide. A key feature of most GI cancers is their slow development, often taking 15 to 20 years from the initial molecular alterations to the onset of invasive disease. This prolonged timeline presents a unique opportunity for early detection and intervention.
In recent years, there has been growing interest in identifying molecular biomarkers that can aid in early detection, prognosis, and prediction of therapeutic response or risk of disease relapse. A key area of focus has been the development of non-invasive liquid biopsy markers. These can be detected in easily accessible bodily fluids, such as blood, urine, and stool, making them particularly suitable for clinical applications.
The major classes of analytes in these assays include cell-free tumor DNA, epigenetic DNA methylation patterns, and transcriptomic markers, including messenger RNAs and small non-coding RNAs. Among these, cell-free RNA analysis is particularly promising due to its robust detection capabilities. However, challenges remain, especially in determining the tissue of origin and ensuring specificity, as multiple cell types can release RNAs. Recent research suggests that analyzing these biomarkers within tumor-derived exosomes or extracellular vesicles in the bloodstream could overcome these limitations. These vesicles, secreted by tumor cells, carry tumor-specific molecular cargo and offer a more reliable source of biomarkers. This presentation will provide an overview of the current state of biomarker development in GI cancers.