Xenografting tumour beneath the renal capsule using modern surgical equipment.

Introduction: The growth of human tumours under the renal capsule in animal models has been performed in the past. However, the use of modern surgical equipment has not always been translated into the laboratory. We report on a novel method for human renal tumour transplants using an automated biopsy gun to obtain tumour tissue and an epidural needle with introducer to easily deploy the grafts under the renal capsule.

Methods: Nude mice had human xenografted tumours grown subcutaneously after implantation of cells from culture. Tumours were then biopsied using a 16-gauge automated biopsy gun. Digital calipers were used to measure a 2-mm segment of the biopsy core that was cut and placed inside a hollow needle (epidural needle). The needle was placed under the renal capsule and the trocar introduced to deploy the graft beneath the capsule with minimal trauma. Further groups had tumour harvested similarly by automated biopsy gun but had the implants placed subcutaneously for comparison.

Results: Tumour grafts were established in 90% of grafted kidneys in this renal subcapsular model (229.68 +/- 118.32 mm(3); mean +/- 95% CI) which compared favourably to the subcutaneous model (163.81 +/- 43.3 mm(3)). Grafts were confirmed by direct observation and histology.

Conclusion: Modern surgical equipment may be utilised to allow tumour transplantation to be precise, with an identifiable and reproducible tumour volume deployed. Surgical researchers and laboratory-based scientists need to embrace new techniques and utilise them to improve models. This model may be adapted to many situations in oncologic research involving xenografting.