Improved colony formation of cultured retinoblastoma cells.

The effect of various components of three semi-solid media on colony formation in two representative retinoblastoma cell lines, Y-79 and WERI, was determined. Diethylaminoethyl dextran was found to be toxic to the cells, and was deleted from the medium. Horse serum was also used without heat treatment. In the most improved culture medium, plating efficiency was 28% for Y-79 cells and 14% for WERI cells, an increase of more than 10 times that of the original formula. In the new medium, both Y-79 and WERI cells showed relatively constant plating efficiency within a certain range, showing that the medium is useful for quantitative clonogenic study of retinoblastoma cells.