SENSITIVITY OF A YOSHIDA SARCOMA TO METHYLENE DIMETHANE SULPHONATE

The action of methylene dimethane sulphonate on the growth rate of the Yoshida sarcoma in rats is described. 1) The tumour, even when established for 12 to 14 days, is unusually sensitive to this alkylating agent and approximately 90% complete cures can be obtained. 2) About 10% of the treated tumours recur and, on retransplantation to new animals, show a marked resistance to the drug. The growth curves of the original and resistant lines, both unilaterally and bilaterally transplanted, following treatment by the drug, are described. 3) Animals in which the original tumour had completely regressed failed to accept a reimplantation of the original or of a resistant tumour. Comparable doses of myleran failed to produce complete regression of the tumour when administered 10 days after transplantation and the level of inhibition was much less than with methylene dimethane sulphonate. Cross‐resistance with triethylene melamine was observed. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company