The intention of this work was to systematically study the presence of
insulin-like growth factor-binding protein 1 and 2 (IGFBP-1 and IGFBP-2) complexes with alpha-2-macroglobulin (α2M) in the circulation of patients with various types of
cancer. Serum samples were collected from patients diagnosed with
cancer and divided into eight groups according to the
tumor type: liver, pancreas, colon, lung, prostate, breast, cervix and ovary. Results obtained for each
cancer group were compared with results obtained for the age and gender-matched controls. Electrophoretic separation and densitometric evaluation of immunoreactive
protein bands were performed. According to our results,
IGFBP-1/α2M and
IGFBP-2/α2M complexes did not exhibit the same presence in different
tumors and were also not uniformly related to the amount of monomer forms. Variations in relative quantities of
IGFBP-1 monomers and complexes in different
tumor types were much more pronounced than those of
IGFBP-2. The amount of
IGFBP-2 monomer increased in sera from all studied patients compared to controls, whereas the amount of
IGFBP-2/α2M complexes most often decreased, being significantly reduced in patients with pancreas, colon, breast or ovary
tumor. Although there is still no confirmation of the physiological role of
IGFBP-2/α2M complexes, their decreased concentration in the circulation provides greater amount of free
IGFBP-2.