Intestinal Microbiome, Oral Microbiome, and Whole Blood Transcriptome Analyses in Gastrointestinal Malignancies

The primary objective of this prospective observational study is to characterize the gut and oral microbiome as well as the whole blood transcriptome in gastrointestinal cancer patients and correlate these findings with cancer type, treatment efficacy and toxicity. Participants will be recruited from existing clinical sites only, no additional clinical sites are needed.