To investigate acquired resistance against targeted therapy, Russo et al. conducted a co-clinical trial and did NGS analysis on gDNA from PDX and ctDNA collected during treatment.117 Moreover, CTC-derived xenografts (CDX) can assist clinicians in identifying the genomic and transcriptomic features of metastatic cancer cells and guiding the treatment against late-stage cancer.118 Faugeroux et al. established a CDX model in the context of prostate cancer and identified that a subclone with TP53 loss triggers cancer metastasis, facilitating the drug screening for patients.119. Here, TP53 is linked to cancer.