Figure 3.

Clonal evolution and heterogeneity, as well as stromal environmental change, in PDX (modified from Shi et al., 2020, Ben-David et al., 2017, Sprouffske et al., 2020, and Cassidy et al., 2015) [10,20,21,22]. (A) Genomic aberrations in PDXs are dynamic and continuous over passaging, fidelity is lost due to CNA variations, selection bias, and clonal evolution. (B) Signaling pathways from stromal cells may not present to the same extent in PDX models as in primary tumors. The stromal environment can have profound effects on transcriptional regulation, but these are often overlooked in PDX models due to stromal replacement.