A simple method of delayed processing of tumor tissue in a soft agar clonogenic assay

Sarcoma 180 tumor tissue from C57 mice was processed in a soft agar clonogenic assay immediately after removal from the animal and after various methods of storage. The sensitivity to the antineoplastic drug cis-platinum was not affected by different storage methods. The highest yield of colony forming cells per 100 mg tumor tissue was 2.3 X 10(4) cells following immediate processing of fresh tumor material. A 24-h storage of solid tumor tissue at 4 degrees C as well as cryopreservation of solid tumor tissue or cryopreservation of a single cell suspension prepared from fresh tumor specimens were found to reduce this value to 24%-37%. Storage of a tumor single cell suspension for 24 h at 4 degrees C however, proved to be a useful and simple method of delayed processing of tumor in a soft agar clonogenic assay. The observed cell yield was 1.91 X 10(4) colony forming cells, 83% of the immediately processed value. If this procedure is suitable for use with human tumor material obtained from biopsies and surgery, the 24 h time interval would be useful for transport from hospital to an appropriate special laboratory. This would result in the broader application of the human soft agar clonogenic assay in predictive testing and drug screening.