Reproducible growth in tissue culture of retinoblastoma tumor specimens.

Retinoblastoma is a unique embryonic tumor which frequently arises because of an autosomal dominantly inherited mutation. Study of the genetic changes associated with retinoblastomas requires techniques that allow proliferation of fresh tumor specimens in tissue culture. However, until the present study, there were no reported methods for routinely obtaining in vitro growth of fresh retinoblastoma tumor cells. When placed on selected fibroblast feeder layers, 65% of fresh retinoblastoma specimens grew; but in the absence of fibroblasts, the same specimens died. Individual fibroblast strains from normal donors, retinoblastoma patients, and mice were effective feeder layers. A fibroblast strain that provided good feeder function for one tumor generally supported growth of other tumors also. Direct contact was required between the tumor cells and the fibroblast; conditioned media alone did not support tumor growth and immobilization of tumor cells in semisolid media above fibroblasts failed to give colony growth. Cultured tumor cells injected into the eyes of athymic nude mice formed tumors histologically characteristic of retinoblastomas.