A new approach to 3D culturing of Wilms tumour cells in vitro has been described in Oncogene. Spheroids representing blastemal, stromal and epithelial Wilms tumour could be successfully grown, providing potential new preclinical models for investigating this disease.

Close inspection of the supernatant from culture of minced Wilms tumour samples revealed the presence of clusters of nonadherent cells. Culture of these cells in low-attachment plates plus rotary shaking and addition of a ROCK inhibitor to prevent anoikis resulted in five long-living 3D spheroid strains of different Wilms tumour histological subtypes. These spheroids could be passaged using mechanical disruption every 1–2 weeks and cultured for >3 years. They could be cryopreserved and revived with a cell viability rate of 60–80%.

Characterization of the spheroids showed that they had the same allele loss pattern, genetic driver mutations, copy number variation and histological appearance as their respective parental tumours. Histological analysis showed that three spheroid strains comprised mostly blastemal cells, one was primarily epithelial in origin and the other contained mainly immature stromal cells.

Spheroids of each type could be successfully genetically manipulated, but stable transduction was not possible for blastemal-type spheroids. Furthermore, spheroids could be successfully xenografted into mice and, in vitro, spheroid cultures derived from xenografts had similar characteristics to the original tumour.

These spheroid cultures can be propagated long term using a simple, low-cost method. They maintain characteristics of the original tumour and can be genetically manipulated and xenografted to enable in vivo study, providing much-needed tools for preclinical investigation of Wilms tumour.