Figure 1. Examples of PDX mis-identification.

PDXs established from either patient A or B are inoculated into a suitable number of mice (four mice in this example at Passage 1). Once the mice reach a defined endpoint, each mouse contributes a large number of samples to expand the biobank (each mouse contributes three samples in this example). Each sample can be serially expanded, as shown in Passage 2. Potential common mistakes involve either mis-labeling (or mismatch) of samples or contamination of one sample with another sample (shown at Passage 3). If mis-identification or contamination is not corrected early, samples can be serially expanded (Passage 4). In the case of contamination if this is not identified early on in the process, a mix of equal parts can lead to competition and a dominant sample can take over (Passage 4).