PRIMARY OBJECTIVES:
I. To quantitatively determine the composition of the microflora and their gene and protein expression levels in patients with metastatic colorectal cancer being treated with fluorouracil (5-FU) based chemotherapy, or anti-PD1 immunotherapy.
SECONDARY OBJECTIVES:
I. Compare the changes in species composition and in the metabolic activities (as determined in the primary objective) with response to chemotherapy or immunotherapy.
II. Compare the changes in species composition and in the metabolic activities (as determined in the primary objective) with toxicities and side effects resulting with chemotherapy or immunotherapy.
OUTLINE:
Patients undergo collection of fecal specimens at baseline, prior to start of each course of chemotherapy or immunotherapy, at the end of weeks 2, 4, 6, and 8, at the end of course 3 and courses thereafter of chemotherapy or immunotherapy, and at the time of disease progression or going off-treatment. Fecal specimens are analyzed via 16S ribosomal ribonucleic acid (RNA) gene sequencing, meta-transcriptomics analysis, and meta-proteomics analysis.
