To investigate adherence capability of cultivated retinoblastoma (RB) tumorspheres with prolonged cultivation

RB cells from two Iranian patients were cultivated in DMEM supplemented with 15% FBS for four weeks in each passage. Fresh medium was added on a weekly basis and immunocytochemistry for synaptophysin was performed. All the experiments were done in duplicate. Cell attachment capability was studied during three consecutive passages

A biphasic population of cultivated cells was observed during the first week in each passage; composed of RB tumorspheres (Figure-1A) and a single-cell suspension overlying a layer of fibroblastic cells that had adhered to the bottom of flask (Figure-1B). Early adherence of RB tumorspheres to the bottom of flask, while surrounded by fibroblasts, was observed in the second week and increased by the fourth week (Figure-1C-E)

Compared to previous data, this study demonstrated the adherence capability of RB tumorspheres to the underlying surface with prolonged cultivation; which after 4 weeks seems to be independent of the fibroblasts