Childhood kidney tumours: in vitro studies and natural history.

The growth patterns of mesoblastic nephroma, Wilms' tumour and bone metastasizing renal tumour of childhood (BMRTC) are distinct from one another and are therefore useful in distinguishing children's kidney tumours. Of the 3 tumour types only BMRTC was able to invade native collagen gels. Fibronectin was present in Wilms' tumour and mesoblastic nephroma, but absent from BMRTC. The readdition of fibronectin to fibronectin depleted tissue culture medium markedly reduced the ability of BMRTC to migrate into collagen gels. The significance of the results and their relevance to the natural history of these neoplasms is discussed.