IGF1 and nasopharyngeal carcinoma: We found that the secretion of IGF-1 by osteoclasts promoted the proliferation of NPC cells, while the secretion of GM-CSF by NPC cells promoted the maturation and differentiation of osteoclasts, that is to say, IGF-1R mediated the crosstalk between the two types of cells, forming a malignant cycle that resulted in the rapid progression of bone metastasis and the further aggravation of bone destruction.