In Vitro Studies on the Anemia of Tumor-Bearing Hamsters

1. Sterile, cell-free extracts of the viable portion of a methylcholanthrene-induced sarcoma of the hamster were capable of hemolyzing in vitro hamster red blood cells from the donor animals, and from animals with homologous and heterologous tumors.

2. Sterile, cell-free extracts of the necrotic material from this same tumor had little in vitro hemolytic action.

3. Whole tumor extracts varied in their in vitro hemolytic activity depending upon the proportion of viable to necrotic tissue present, with the maximum hemolysis observed when the whole tumor contained more viable than necrotic tissue.

4. Sterile, cell-free extracts of normal hamster liver had a strong hemolytic action on a whole range of red blood cells.

5. Hemolysins elaborated by the viable tissue in transplanted hamster tumors may be one factor contributing to the anemia in hamsters bearing transplantable sarcomas.