Hyperthermic modulation of macrophage-tumor cell interactions.

Hyperthermia in the febrile (less than or equal to 41 degrees C) or tumor therapeutic (greater than or equal to 42 degrees C) ranges is known to alter tumor-host interactions: there are reports of either inhibitory or enhancing effects on tumor metastasis and various host defense mechanisms. Historically, this has been an area of conflicting and often anecdotal reports, and there are still significant gaps in our knowledge of the effects of temperature on tumor-host interactions. However, we believe that the tools are now available to further our understanding of the complex relationships between febrile episodes or therapeutically applied heat and various tumor-host cytotoxic mechanisms, and that potentially important and exploitable relationships can be defined. In this review we give an overview of the current status of this field and the factors that have shaped it. We also describe our recent experimental work with macrophages and their monokines, primarily tumor necrosis factor (TNF), which we feel offers new scientific and clinical opportunities for future studies.