Fig. 1

Schematic overview of the study. Biospecimens from a total of 69 stage IV melanoma patients (showing no signs of infection) were analysed across two groups: (1) with matching patient stool, saliva and plasma samples and (2) with plasma samples only. Samples were extracted for DNA in different batches totalling n = 1 for stool, n = 1 for saliva and n = 5 for plasma (batches A–E). Thirteen of the sixteen samples of batch A matched samples of batch B. The number of DNA-Extraction-Negative-Controls (DENCs) extracted in each one of the depicted batches from left (batch St) to right (batch E) were 12, 6, 9, 9, 8, 8 and 8 respectively. All samples were amplified for the 16S rRNA gene and sequenced across two MiSeq runs that correspond to each one of the two groups