THE EXPRESSION OF MESSENGER-RNA FOR INSULIN-LIKE GROWTH-FACTORS AND THEIR RECEPTOR IN GIANT-CELL TUMORS OF HUMAN BONE

Insulin-like growth factors I and II are among the most abundant growt h factors found in bone, and their expression also has been reported i n a variety of neoplastic tissues. Using the technique of in situ hybr idization, the authors have studied the expression of the messenger ri bonucleic acid (mRNA) for insulinlike growth factors I and II and the Type 1 insulin-like growth factor receptor in giant cell tumors of hum an bone (n = 8). The expression of the mRNA for insulin-like growth fa ctors I and II and the Type 1 insulin-like growth factor receptor was observed in giant cells and in the mononuclear stromal cell component but not in cells of the fibrous connective tissue at the growing edge of the tumor. The multinucleated cells expressed tartrate resistant ac id phosphatase and showed reactivity with osteoclast selective monoclo nal antibodies, confirming the close relationship between these giant cells and osteoclasts. Thus, these results are consistent with the pos sibility that locally produced insulin-like growth factors have an imp ortant regulatory role in the growth and development of giant cell tum ors of bone. In addition, they suggest that these growth factors may f unction as autocrine or paracrine regulators of the proliferation and differentiation of cells of the osteoclast lineage.