Influence of iron on in vivo proliferation and lethality of L1210 cells.

The ability of iron to stimulate the growth of L1210 cells both in DBA-2 mice and in cell culture is evaluated. Although in vitro stimulation is absent, in vivo studies clearly indicate higher numbers of tumor cells in the presence of supplemental iron. When mice were given iron i.p., at levels comparable to clinical doses for humans (24 mg/kg body weight), the tumor load recovered from their peritoneum was substantially greater than from controls without iron supplements. Furthermore, at higher levels of supplemental iron (250 mg Fe/kg body weight), the pretreated animals inoculated with L1210 cells died in 9.7 d whereas controls died in 12.2 d (i.e., 25% faster). As expected, the lower iron dose (24 mg/kg) also resulted in shorter life spans, although the effects were less striking. It is the belief of these authors that these data support the opinion that "anemia of chronic disease" associated with leukemia and possibly other malignancies may represent a host defense mechanism as has been postulated by others (1, 8).