ABSTRACT
For most of medical history, therapeutic intervention has relied on exogenous factors. These treatments have run the gamut from magical incantations, to animal- and plant-derived substances, and finally to rational drug design by combinatorial chemistry. The majority of cytokines are glycoproteins secreted by cells, although membrane-associated forms have also been described. Cytokines are generally not produced constitutively but rather in response to cellular activation. Cytokine production is highly regulated in both paracrine and autocrine fashions at the transcriptional and posttranscriptional levels. One of the most thoroughly investigated therapeutic uses of cytokines thus far has been in the treatment of neoplastic disease. Owing to the intrinsically complex nature of neoplastic disease, it follows that the use of cytokines for treatment is equally complex. Therapeutic options to date include disruption of autocrine growth, enhancement of natural immune resistance, the use of cytokines in combination with other drugs, and direct tumor cytotoxicity by cytokines.
