Establishment of a hepatocellular carcinoma patient‐derived xenograft platform and its application in biomarker identification

Using a method optimized in hepatocellular carcinoma (HCC), we established patient‐derived xenograft (PDX) models with an increased take rate (42.2%) and demonstrated that FBS +10% dimethyl sulfoxide exhibited the highest tumor take rate efficacy. Among 254 HCC patients, 103 stably transplantable xenograft lines that could be serially passaged, cryopreserved and revived were established. These lines maintained the diversity of HCC and the essential features of the original specimens at the histological, transcriptome, proteomic and genomic levels. Tumor engraftment was associated with lack of encapsulation, poor tumor differentiation, large size and overexpression of cancer stem cell biomarkers, and was an independent predictor for overall survival and tumor recurrence after resection. To confirm the preclinical value of the PDX model in HCC treatment, several antitumor agents were tested in 16 selected PDX models. The results revealed a high degree of pharmacologic heterogeneity in the cohort, as well as heterogeneity to different agents in the same individual. The sorafenib responses observed between HCC patients and the corresponding PDXs were also consistent. After molecular characterization of the PDX models, we explored the predictive markers for sorafenib response and found that mitogen‐activated protein kinase kinase kinase 1 (MAP3K1) might play an important role in sorafenib resistance and sorafenib response is impaired in patients with MAP3K1 downexpression. Our results indicated that PDX models could accurately reproduce patient tumors biology and could aid in the discovery of new treatments to advance in precision medicine. What's new? Patient‐derived xenografts (PDX) models offer a promising preclinical tool. Here, the authors established the largest bank of hepatocellular carcinoma (HCC) PDX models with a high and stable tumor take rate that recapitulated the key clinical and molecular characteristics of primary tumors. The tumor take rate was associated with expression of cancer stem cell proteins, lack of tumor encapsulation, poor differentiation, advanced stage, overall survival, and time to recurrence in patients. The models were used to identify MAP3K1 expression as an indicator of patient response to sorafenib treatment. PDX models are valuable surrogates for HCC patients and could facilitate translational research.