Tumor-specific blood serum factors as determinants of tumor growth.

: In the present review, we focus on the importance of blood serum factors for tumor growth in vivo. Data from mice experiments indicate the existence of serum factors, which increase the mitotic index of Ehrlich carcinoma cells from 15 to 80%. The impaired production of these factors increases the life span of tumor-bearing animals from 14-20 days to 90 days. Blocking the production of tumor-specific factors causes the complete regression of already developed Ehrlich carcinoma. These serum factors do not affect the malignant carcinoma cells in vitro. We identified serpins as tumor-specific serum factors. Experimental evidence suggests that serpins are not only essential for tumor growth. Serpins are also involved in the regeneration of normal tissues, such - as adipose tissue, recurrence after cosmetic operations (liposuction), inhibiting rejection after liver transplantation, protection of parasitic flat worms living in host tissues and organs etc. We conclude that the inhibition ofserum factors may represent attractive novel strategies for the prevention and treatment of relapsed cancers.