Insulin-Like Growth Factor System in Cancer: Novel Targeted Therapies

Table 2

Human insulin-like growth factor binding proteins.

IGFBPs	Mass (kDa)	Source of purification	Relative binding affinity for IGFs
IGFBP1	25.0	Amniotic fluid, placenta	IGFI = IGFII
IGFBP-2	31.3	BRL-3A and MDBK cells, human serum	IGFII > IGFI
IGFBP-3	28.7	Plasma	IGFI = IGFII
IGFBP-4	25.9	Human osteosarcomas, prostatic carcinoma, colon carcinoma, and glioblastoma	IGFI = IGFII
IGFBP-5	28.5	C2 myoblasts conditioned media, human bone	IGFI = IGFII
IGFBP-6	22.8	Cerebrospinal fluid, human serum	IGFII > IGFI