Effects of cytokines on in vitro colony formation of primary human tumour specimens.

Although under study to alleviate chemotherapy-induced bone marrow toxicity, cytokines can stimulate in vitro growth of solid human tumour cell lines. The effects of granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF) and interleukin-3 (IL-3) on in vitro colony formation of primary human tumours was studied in a capillary soft-agar cloning system. Of 108 tumour specimens from 100 patients, 85 specimens were tested against all three factors at concentrations ranging from 0.1 to 1000 ng/ml. 44 of 100 tumours showed adequate growth in controls. 8 out of 43 (19%) specimens were significantly stimulated by GM-CSF, 6 of 40 (15%) by G-CSF and 10 of 44 (23%) by IL-3. Sensitivity to all three cytokines was observed in 4 of 44 (9%) specimens. By light microscopy the appearance of colonies from stimulated specimens was identical to that of controls. Sensitivity to cytokines was independent from sensitivity to epidermal growth factor, transferrin or insulin. Sensitivity to GM-CSF, G-CSF and IL-3 may be aberrantly expressed in a subgroup of solid human tumours.