Viability of forty-two neoplasms after long-term storage in liquid nitrogen at −195 °C

Abstract

Forty-two neoplasms stored at −195 °C for periods up to 6 years have remained transplantable and lethal to their inoculated hosts. A bioassay which estimates the surviving cell population based on the cell kinetics of exponentially growing neoplasms in vivo demonstrated an initial loss of viable cells due to the freezing procedures and no further losses due to storage. The response of 14 drug-induced resistant neoplasms to chemotherapeutic agents has remained unaltered after long-term storage.