The development of an ascites tumor from a transplant

able squamous cell carcinoma of mouse was reported several years ago (9). It appeared then to be the only reported instance of an experimental adaptation of a squa mous cell carcinoma to an ascitic form of growth. Be cause this ascites tumor consisted of a highly anaplastic cellular population, which differed markedly from defi nitely squamous components of the parent solid tumor, more work was required to throw light on the factors responsible for the observed inconsistencies. Since then several investigators have studied a related ascites tumor, MT890, which was developed subsequently (6, 12—14). Later attempts to produce new ascites tumors from the original transplantable solid carcinoma, MT7O, by the direct i.p. inoculations of mice, resulted in the develop ment of new ascitic tumors which were subjected to in vestigation (11, 15). The present study was undertaken before these new tumors were developed. Therefore, new methods were sought for the adaptation of cells from a transplantable squamous cell carcinoma of mouse to growth in the intraperitoneal environment. It soon became apparent that a tissue culture cell line already developed from this tumor (3) provided a logical source of inoculum for testing its ability to develop ascitic tumors. This paper is concerned with the technics used to obtain ascites tumors from tissue culture cell lines and describes the development of new tissue culture cell lines derived in the course of this work. Other reports mention the ability of cells from certain ascites tumors to grow in tissue culture (1, 2, 7, 8). How ever, no reports of a successful use of tissue culture cell lines for the production and study of ascites tumors origi nating from a squamous cell carcinoma were found.