Frozen preservation of human malignant tumors transplanted into nude mice

Five transplantable tumors, which originated from human maligant neoplasms and had been maintained in nude mice, were frozen at--70 degrees preserved for 1226 days. Tumor tissue was minced in a mixture of tissue culture medium, 10% dimethyl sulfoxide, and 10% calf serum before freezing. The transplantability of frozen tumors was examined after thawing. Morphological and functional characteristic of each tumor were compared before and after the frozen storage. The results suggest that low-temperature preservation technique can be applied satisfactorily for the maintenance of human malignant tumors which have been maintained by using nude mice.