Modulations in mouse hemopoiesis after engraftment with Lewis lung (3LL) carcinoma cells.

Hemopoietic changes in male C57BL/6Cum BR mice engrafted with Lewis lung carcinoma (3LL) were evaluated between day 7, when palpable tumors were present, to day 30 postengraftment. All experimental animals demonstrated decreasing hematocrits (down 40% by day 30) with concurrent leukocytosis which by day 30 postengraftment had reached levels 13.4 times normal. The myelocytic/erythrocytic ratio for normal animals was 1:3 (bone marrow: spleen). The ratio for engrafted animals ranged between 10:1 and 40:1. This apparent shift in production priorities is even more significant in light of the fact that femoral bone marrow cellularity had decreased by 33% on day 17. Splenomegaly, evident by day 7, was seven times control by day 17. Clonogenic analysis of erythroprogenitor cell concentrations revealed an inverse relationship between bone marrow and spleen. 27 days after engraftment, splenic populations demonstrated significant increases in colony forming unit-erythroid (115-fold), burst forming unit-erythroid (7.4-fold), whereas bone marrow concentrations had decreased (6-fold). This report suggests that initiation of 3LL tumor in mice results in a change in the degree of hematopoietic priorities and participation of erythroid organs.