Sarcoma induced after Methylcholanthrene intramuscular administration to C_<57>BL mouse was transplanted in the same inbred mouse. Tissue cultures of the above established sarcoma were then prepared.
When the colony grew to an appropriate size (the number of cells being 1×10^2 or more per colony) in the Petri dish, a sterile cylinder was set up surrounding one colony and pipetting was done to pick up the tumor cells in the colony. After that, the tumor cells were cultured in a CO_2 incubator.
A clone system of the transplantable sarcoma was established.