A serum-free medium for the Courtenay-Mills soft agar assay.

A serum-free medium has been developed to support the clonogenic growth in soft agar of human cervical carcinoma cell lines xenografted into nude mice. Using the Courtenay-Mills assay, colony-forming efficiencies and colony sizes equivalent to those obtained using Ham's F12 plus 15% fetal calf serum can be obtained. Validation of the assay using the developed medium was obtained through establishing linearity between the number of cells plated and colonies formed, and by producing radiation survival curves.