A spontaneous ascites tumor originating and transplantable in the Wistar rat.

tumor which would be transplantable in a non-inbred strain of rats as widely used as the Wistar strain, the authors have, in the course of the past several years, transplanted a number of spontaneous tu mors originating in Wistar rats. None of these transplants, however, survived the first passage. Recently, an adult Wistar rat with a spontane ous ascites tumor was brought to the attention of the authors. Studies on the transplantation and characteristics of this tumor form the basis for this report. In studies of problems of aging in the Wistar In stitute colony, Farris and Yeakel (2) found several spontaneous tumors which were diagnosed as re ticulum-cell sarcomas, accompanied by an accu mulation of fluid in the peritoneal cavity. With the exception of the well known Yoshida sarcoma (9, 10) which may have been of spontaneous origin, a search of the literature has not revealed the exist ence of a spontaneous ascites tumor originating in a rat that has been successfully transmitted serial ly from the original host as an ascites tumor. The possibility that the Yoshida sarcoma may have re sulted from feeding with o-amidoazotoluol fol lowed by cutaneous application of potassium ar senite solution (9) must be considered. It is stressed, therefore, that the rats in the Wistar colony are not subjected to treatment with chemi cats or carcinogens. Their normal diet consists of the standard Purina Dog Chow, ad libitum, with no supplements. MATERIALS AND METHODS An adult female Wistar rat, 7 months and 11 days of age, with a distended abdomen was ether ized, and approximately 50 ml. of ascitic fluid was withdrawn by puncturing the abdominal wall with a 13-gauge trocar. One ml. of this fluid was inject ed intraperitoneally into each of two 30-day-old rats (taken at random) from the Wistar colony. Exposure of the abdominal cavity revealed that the mesentery,omentum, and fatty tissue surround ing the ovaries and uterine horns, as well as other fatty tissues in the pelvic cavity, were studded with nodular tumors. Several of the nodules were excised, minced with a scissors, and then trans planted subcutaneously into three Wistar rats. In the serial passages, a standard inoculum of 1 ml. of the ascitic fluid and a full 13-gauge trocar of the solid tumor tissue was used. All rats used in this study were from 30 to 32 days old. To deter mine whether sex would subsequently influence …