Analysis of incipient growth of Yoshida sarcoma in vivo after transplantation of a small number of tumor cells.

Incipient growth of Yoshida sarcoma in ascitic and solid forms was analyzed after transplantation of a small number of tumor cells varying from 1 to 10(6). Growth curves of the ascites tumors revealed that the duration of the incipient growth was much longer than the length of subsequent advanced stage and that the ascites tumor during its incipient stage appeared to grow exponentially and most rapidly in the entire course of the tumor development. Growth rate analyses of the ascites and solid tumors showed that, during their incipient stage, the population doubling time prolonged gradually as the inoculum size increased. This phenomenon was thought to suggest probable cell death on account of the transplantation procedure.