Stool Bacteriomic Profiling in Patients with Metastatic Renal Cell Carcinoma Receiving Vascular Endothelial Growth Factor-Tyrosine Kinase Inhibitors.

PURPOSE Diarrhea occurs in approximately half of patients with metastatic renal cell carcinoma (mRCC) receiving vascular endothelial growth factor-tyrosine kinase inhibitors (VEGF-TKI). We evaluated the relationship between VEGF-TKI-related diarrhea and stool microbiota. EXPERIMENTAL DESIGN Stool samples were collected from 20 mRCC patients receiving VEGF-TKIs. 16S rRNA sequencing was used to characterize the stool bacteriomic profiling of patients. Assay validation with Salmonella typhimurium spike-in experiments suggested greatest speciation with use of the V5 region. RESULTS Higher levels of Bacteroides spp. and lower levels of Prevotella spp. were found in patients with diarrhea. In addition, patients receiving VEGF-TKIs with mRCC appeared to have less relative abundance of Bifidobacterium spp. as compared with previous reports based on healthy subjects. CONCLUSIONS We have thus demonstrated interplay between microbiota and VEGF-TKI-induced diarrhea. Further studies are warranted to evaluate the potential causative role of preexisting dysbiosis in VEGF-TKI-related diarrhea.