In vitro and in vivo growth of an intraocular retinoblastoma-like tumour in F-344 rats.

Retinoblastoma-like cells grew in colonies on the bottom of tissue culture flasks. The population doubling time was 19 h. Tumour cells from cell cultures had a 39% plating efficiency, and fresh tumour cells from intraocular tumours had a 32% plating efficiency in colony forming assays. Inoculation of 1.5 X 10(4) tumour cells in the vitreous of F-344 rats resulted in a 100% tumour take and regularly growing tumours with a doubling time of 3 days. The tumour take-rate was not changed in wholebody immunosuppressed animals. The tumour volume was assessed under a stereo microscope, and it was possible to divide the tumours into 4 groups according to the number of intraocular tumour cells. Tumour growth caused eye perforation in 89% of the inoculated eyes. Spontaneous tumour regression was not seen in non-perforation groups. Immunosuppression with whole-body irradiation and dense traumatic cataract had no significant effect on the growth. It is concluded that this animal retinoblastoma-like tumour is suitable for quantitative therapy studies in vivo and in vitro.