Successful Secondary Engraftment of Pancreatic Ductal Adenocarcinoma and Cholangiocarcinoma Patient-Derived Xenografts After Previous Failed Primary Engraftment

Abstract

BACKGROUND: Patient-derived xenografts (PDX) provide histologically accurate cancer models that recapitulate patient malignant phenotype and allow for highly correlative oncologic in-vivo downstream translational studies. Primary PDX engraftment failure has significant negative consequences on programmatic efficiency and resource utilization and is due to either no tumor growth or development of lymphoproliferative tumors. We aimed to determine if secondary engraftment of previously cryopreserved patient tumor tissues would allow salvage of PDX models that failed previous primary engraftment and increase overall engraftment efficiency. METHODS: Patient hepatobiliary and pancreatic cancers that failed primary engraftment were identified. Previously cryopreserved primary patient cancerous tissues were implanted into immunodeficient mice (NOD/SCID). Mice were monitored, growth metrics calculated, and secondary engraftment outcomes were recorded. Established PDX were verified and compared to original patient tissue through multiple generations by a GI pathologist. RESULTS: We identified 55 patient tumors that previously failed primary engraftment: no tumor growth (n = 46, 84%) or lymphoproliferative tumor (LT) (n = 9, 16%). After secondary implantation using cryopreserved patient tissues, 29 new histologically validated PDX models were generated with an overall secondary engraftment rate of 53% for all tumor types with greatest yield in pancreatic and biliary tract cancers. Of the secondary engraftment failures (n = 26), 21 (38%) were due to no growth and 5 (9%) developed LT. CONCLUSION: Secondary PDX engraftment using cryopreserved primary cancerous is feasible after previous failed engraftment attempts and can result in a 50% increase in overall engraftment efficiency with decreases in LT formation. This technique allows for salvage of critical patient PDX models that would otherwise not exist. SYNOPSIS: Patient-derived xenografts have many important translational applications however can be limited by engraftment failure. We demonstrate optimized methodology utilizing cryopreservation of primary tumor tissue that allows for subsequent successful secondary engraftment and creation of PDX models that failed previous primary engraftment and allowed salvage of patient PDX models that would otherwise not exist.

Prognostic value of patient‐derived xenograft engraftment in pediatric sarcomas

“…Other studies have evaluated some of the technical factors addressed in our study, such as sample conservation. In agreement with our results, cryopreserved pancreatic cancer biopsies engrafted efficiently in mice [37]. We did not evaluate 'engraftment site' as a factor, but the orthotopic site is especially relevant to reproduce the complex microenvironment necessary for the growth of central nervous system tumors [38][39][40], and could facilitate and accelerate tumor implantation and recapitulate patient tumor characteristics [41,42].…”

Impact of immediate cryopreservation on the establishment of patient derived xenografts from head and neck cancer patients

“…Whether our results translate to other malignancies requires further study. Hernandez and colleagues assessed a similar approach in hepatobiliary and pancreatic cancers and demonstrated similar findings [ 17 ] suggesting that this approach is likely to work in a wide variety of cancer types. In addition, while we have focused on the potential benefits of cryopreserving samples prior to implantation, we acknowledge that this requires us to perform our characterization on a cohort of patients whose tumors may never establish PDXs.…”

The Application Progress of Patient-Derived Tumor Xenograft Models After Cholangiocarcinoma Surgeries

“…Then, 17 cases of CCA were immediately cryopreserved and implanted with resuscitation. In mice, 12 cases (70%) of PDX models of CCA were successfully constructed under the skin, which proved that long-term preservation of CCA could be achieved using cryopreservation technology (35).…”