Concordance and Deviations of the PDX Tumors from the Primary Tumors of NSCLC Patients: Effects of Murine Fibroblasts on Low Engraftment Rates

Patient-Derived Xenograft (PDX) models of primary lung cancer have been reported. However, varying engraftment rates and their underlying mechanisms for specific subtypes of lung cancer (adenocarcinoma, squamous cell carcinoma, and large cell neuroendocrine carcinoma) have not been studied. The authors prepared subcutaneous tumors grown in NOD Scid Gamma Mouse (NSG^™) mice with primary tumors of lung cancer patients to develop lung cancer PDX models. Pathological features of the subcutaneous tumors were compared with those of the patients. One hundred 7teen lung cancer PDX models retaining the original pathologic features were obtained from 642 primary lung cancer patients. Nineteen PDX tumors and the corresponding patient tumors, representing three subtypes of lung cancer, were selected and analyzed with in-depth genomic and transcriptomic profiling. Results showed the PDX tumors retained most of the somatic and oncogenic mutations with limited levels of additional xenograft- specific mutations. Significant downregulation of the genes involved in hypoxia-associated angiogenesis was found compared with the corresponding human tumors. This downregulation was associated with murine fibroblasts in the PDX tumor microenvironment, which might be an important factor in low engraftment rates in primary lung cancer PDX models.