Culture of retinoblastoma cells from clinical specimens: growth-promoting effect of 2-mercaptoethanol.

Establishment of new tumor cell lines is an important first step for biological studies of tumor cells. High success rates in establishing retinoblastoma cell lines have been reported when feeder-layer culture but not liquid-culture techniques were used. Liquid culture is, however, essential for studies in which feeder-layer cells are undesirable. In a previous study, we formulated a medium (RB-- medium), the components of which were almost identical to those of a soft-agar medium developed for colony formation of established retinoblastoma cell lines, in which one cell line from 12 primary retinoblastoma specimens was established. In this study, another medium (RB++ medium), RB-- medium to which 20 microM 2-mercaptoethanol and 375 microM asparagine were added, was tested for its ability to grow retinoblastoma cells from clinical specimens. In the RB++ medium, 6 cell lines from 16 primary sites, 2 from 2 intraocular-recurrent and 3 from 3 metastatic retinoblastomas grew for over a year. The major reason for the apparent improvement of the RB++ medium on the RB-- medium was demonstrated to be the addition of 2-mercaptoethanol.