Fig. 1

Flow chart of the biodistribution study under GLP conditions. The methods and decision points shown in continuous lines and rectangles were performed within the presented biodistribution study. Steps in dashed lines were prospectively planned but were not necessary to perform. Methods shown as a rhombus may have at least two outcomes. The Roman numerals are used in order to match each step in this flow chart with the corresponding explanation in the “Results” section. ^aHuChon spheroids from five different patients were implanted, eight mice were treated per patient, each treated with 1 spheroid, and thus 40 mice were analyzed. ^bIn mouse MB1 (1/40) the huChon spheroid could not clearly be identified macroscopically at the implantation site. Thus, complete qPCR analyses of organs were performed. ^c17 samples could not be evaluated (n.e.) by IHC due to technical reasons. The further analyses of these mice are shown in an additional flow chart in the Supplement (Additional file 3: Figure S3). In case of detection of human cells or DNA within the five selected organ/tissue types (lungs, liver, left and right kidney, spleen, and pooled local lymph nodes) the study would have to be repeated with a second cohort of 40 mice with a follow up of 61 ± 1 days. If biodistribution had been confirmed, the upstream tumorigenicity study (see below) would be performed with particular attention to the afflicted organs