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.