Hemolytic Action of Mouse Mammary Carcinoma Filtrate on Mouse Erythrocytes in vitro.

Although the association of cancer with anemia has long been observed, no satisfactory explanation of the mechanism of this relationship has yet been furnished. 1 Experiments reported in this study appear to suggest that, at least in the case of mammary carcinoma of mice, a direct destructive action of a filterable substance contained in the tumor cells, on the erythrocytes of the host, should be taken into consideration. Thus, filtrates prepared from mouse mammary carcinomas were found to destroy mouse erythrocytes in vitro. The following technic was employed to demonstrate this hemolytic property of the tumor extracts:

Materials and Methods. Tumor extracts. Ten different mammary carcinomas that developed spontaneously in old C3H females, and 2 transplanted tumors that originated as mammary carcinomas in C3H females and have been carried through successive transplantations in these animals, 2 were used as the source of the tumor extracts. A freshly prepared extract from a single tumor was used for each test. The tumors were removed aseptically, weighed, and ground for several minutes in a porcelain mortar, 0.85% solution of sodium chloride being added to obtain cell suspensions varying from 15 to 30%. The suspensions thus obtained were cleared by centrifugation at 5000 t.p.m. for 10 minutes, and the supernatant fluid was then passed through a Seitz (No. 3) filter; the resulting filtrate was designated “filtered extract,” and was used for some of the tests. In other experiments, the tumor cell suspensions were cleared by 3 successive centrifugations at 5000 t.p.m. of 10 minutes each; the final supernatant fluid was designated “centrifugated extract” and used for the tests. Both filtered and centrifugated tumor extracts were bacteriologically sterile as evidenced by negative inoculations of ordinary culture media.

Erythrocytes. Blood was drawn directly from the heart of an etherized mouse of either the C3H 2 , 3 or Ak 4 inbred lines, or of the An 2 subline. The oxalated red blood corpuscles (RBC) were washed twice at 3,000 t.p.m. for 5 minutes, and a final 1% suspension of RBC in 0.85% solution of sodium chloride was prepared.