Growth and radiosensitivity testing of human tumour cells using the adhesive tumour cell culture system

The radiosensitivity of human tumour cell lines and cells cultured from xenografts or biopsy specimens was measured using the adhesive tumour cell culture system (ATCCS). For cell lines the derived surviving fractions at 2 Gy were in good agreement with values obtained by clonogenic assay. However, the assay tended to overestimate survival at higher radiation doses, and thus to give a false impression of radioresistance. When cells taken from xenografts or tumour biopsies were cultured there was no evidence for selective growth of tumour cells: fibroblast-like cells commonly grew. Immunohistochemical staining against the intermediate filament, vimentin, supported the mesenchymal origin of the fibroblast-like cells. In cultures of artificial mixtures of tumour cells and fibroblasts, low proportions of fibroblasts were not excluded by the assay and consequently modified the radiation response. The majority of cultures grown from bladder carcinoma biopsy specimens appeared fibroblast-like, although in some cases clearly distinguishable colonies of tumour cells were also grown. In such tumour types the reliable measurement of radiosensitivity in cells taken from biopsies will require further development of techniques that allow the selective growth of tumour cells.