Representative tumorsphere and attached phenotypes of cultures derived from primary retinoblastoma tumor cells.

Biopsies from human Rb tumor cells were placed in culture medium. Cultures arose either as three-dimensional spherical aggregates of cells called tumorspheres or as an attached monolayer. Typically, tumorspheres arose when Rb cells were placed in neural stem cell-optimized medium without serum, and adherent cultures arose when Rb cells were placed in classical medium with FBS. However, in rare cases tumorspheres and attached cells both arose from Rb cells placed in classical medium with FBS. Scale bar = 100 µm.