Background: Cytokines were shown both to enhance tumour growth and formation of metastases and to inhibit proliferation of tumour cells. TNF alpha may mediate apoptosis and necrosis of cancer cells, the exact role of IL-2 remains to be elucidated. Plasma levels of TNF alpha and TNF and IL-2 soluble receptors (sTNF-R, sIL-2R) should thus be in some relation to the biological characteristics of the breast cancer.
Methods and results: Plasma levels of TNF alpha, sTNF-R I and II and sIL-2R were measured in 31 women with different stages of breast cancer both before the institution of the therapy and after 3 months of the treatment. Plasma levels of both types of sTNF-Rs were higher in patients with breast cancer than in controls (sTNF-R I-2166.6 +/- 568.9 VS. 1121.3 +/- 260.6 pg/ml, p < 0.001, sTNF-R II-3792.8 +/- 958.9 vs. 1996.2 +/- 404.3 pg/ml, p < 0.001) with no significant difference between clinical stages. Plasma levels of both sTNF-R (0.871, p < 0.001) and sIL-2R tightly correlated one with each other. Plasma levels of TNF alpha decreased after treatment (from 3.92 +/- 1.86 to 3.40 +/- 1.15 pg/ml, p < 0.001), but plasma levels of sTNF-Rs and sIL-2R were not influenced by the treatment.
Conclusions: Plasma levels of soluble TNF receptors may thus serve as a non-specific marker of the untreated breast cancer. Their relation to other biologic characteristics of this tumour is not clear. It remains also to be clarified if the long-term treatment leads to the normalization of sTNF-Rs plasma levels.