The Evolving Landscape, Clinical Implications and Future Perspective of Biomarkers in Gastrointestinal Cancers

Gastrointestinal (GI) cancers are a major public health problem worldwide. Early GI cancer detection, pretherapeutic responsiveness prediction, and postoperative micro-metastasis monitoring are the hallmarks for successful GI cancer treatment. The approval of novel therapies for metastatic GI cancer (mGIC) has led to important improvements in patient outcomes. Despite the multitude of treatments available, outcomes and toxicity with each regimen can very markedly from patient to patient. Therefore, it is still necessary to increase individualization of treatments based on tumor genetic profiles to optimize efficacy, while minimizing toxicity. As such, there is currently a great focus on the discovery and validation of biomarkers in mGIC, with many new potential prognostic and predictive markers being identified alongside developments in molecular profiling technologies. New technologies such as next generation sequencing (NGS) and customized genetic panels have highlighted the potential predictive and prognostic roles. There is a clear need for evidence-based recommendations to guide the use of validated and emerging biomarkers in clinical practice. Furthermore, the future perspective of emerging biomarkers development for the medical unmet need for GI cancer patients is mandatory.

This Research Topic aims at elaborating the progress on the clinical utility of emerging biomarkers that are used for auxiliary early diagnosis, treatment decisions and postoperative surveillance for patients with GI cancers (excluding Gastric cancer). We also would like to discuss the continued prospective validation of biomarkers along with further developments in patient molecular profiling technologies which will help to achieve the goal of true individualized therapy.

We welcome submissions of Review, Mini Review, Original Research, and Clinical Trial on the sub-themes below for GI cancer (excluding Gastric Cancer) patients, which will be related to circulating tumor cells, miRNAs, tumor microenvironment, and new therapeutic regimen.

• Predictive or prognostic biomarkers that can be used for individualized treatment.
• Predictive or prognostic biomarkers that can be used to predict the oncological outcomes or toxicities.
• Biomarkers related to cancer metabolism or drug-resistance.

Note: submissions on similar topics for Gastric cancer are not in scope of this Research Topic and need to be submitted to the Research Topics "Gastric Cancer Phenotype and Treatment" at https://www.frontiersin.org/research-topics/14602 or "Molecular Biomarkers for Gastric Cancer" at https://www.frontiersin.org/research-topics/13667.