Rapid hyperthermic cell sensitivity test measured by RNA synthesis using contact-sensitive plates of confluent Balb/c 3T3 cell monolayers.

We have developed a hyperthermic sensitivity test for human neoplastic cells using contact-sensitive confluent monolayers of BALB/c 3T3 cells designated as 'contact-sensitive plates (CSP)', which almost completely inhibited the growth of normal cells without influencing the growth of the human neoplastic cells. On 'CSP', the relative [3H]uridine incorporation into RNA of the hyperthermic cultures showed an excellent correlation with the relative clonogenic efficiency of the treated cultures. Since 'CSP' allows for only contact-insensitive tumour cells to proliferate, our assay will predict the hyperthermic sensitivity of only the neoplastic cells. Moreover, even 2 x 10(3) cells derived from clinical tumour tissues can be assayed within only 3 days. This assay system is potentially used as a rapid in vitro hyperthermic sensitivity test for human carcinoma.