Differentiation of “Normal” and Neoplastic Cells Maintained in Tissue Culture by Implantation into Normal Hamsters. ∗

Summary

Quantitated inocula of 14 tissue culture cell lines which are remarkably similar in vitro were implanted into cheek pouches of unconditioned Syrian hamsters. All cell lines grew in the cheek pouch when 1 × 10⁶ cells were implanted, but only those cell lines derived from neoplastic tissue produced tumors when inocula contained 1 × 10⁴ cells. Other experiments indicated that this difference in the growth potential of cell lines deriving from neoplastic tissue also may be delineated in hamsters conditioned with cortisone acetate by implantation with 1 × 10³ or fewer cells.