HORMONE-DEPENDENT TUMOURS AND SYSTEM OF INSULINE-LIKE GROWTH FACTORS (review of the literature)
The IGF system including IGF ligands, their receptors and IGF binding proteins connected by uneasily regulated interrelations, also interacts with some other biological regulators of cell proliferation and growth. IGF system components modulate normal growth processes and tumor growth. IGF-1 inhibits apoptosis and stimulates cell proliferation. Laboratory and clinical investigations show that IGF signaling pathway plays an important role at all stages of tumor development: malignant transformation of cells, tumor growth, invasion and metastasizing as well as resistance to treatment. In this connection, the strategies of IGF effects inhibition are yet under investigation - those (1) blocking IGF-receptor binding, (2) using endogenous inhibitors of IGF effects in tissue - IGFBP, which can neutralize IGF ligands and block IGF-receptor activation, and (3) using specific inhibitors against internal IGF-R1 tyrosine kinase.